What is TCP/IP?

TCP and IP are two different communication protocols that complement each other’s functionality.

The Internet protocol or IP delivers (routes and addresses) data packets between a source (device or application) and their destination. It makes sure that those packets arrive at the right destination. It defines the rules and formats for applications and devices to communicate and exchange those data packets on a specific network or across different connected networks. 

The transmission control protocol or TCP organizes data in a specific manner to protect them while exchanged between a client and a server. It’s a very used protocol on networks by all types of devices and applications. TCP protects data’s integrity from the sending and all the way to their delivery.

The development of these protocols (TCP/IP) happened in the 1970s. In that decade, the ARPANET became really popular, which motivated the creation of more networks to connect different organizations. Since those networks used a different protocol to send data back and forth, they could not communicate among them. The creation of a technology that could work as an intermediary to allow such communication became a need. 

The combination of TCP and IP and its official adoption as the standard protocol -in 1983-for ARPANET (Internet’s predecessor) was the solution. No matter what other protocols networks used, if they supported TCP/IP, they could communicate with all the TCP/IP networks that existed.

The two technologies, TCP and IP, became the technical base for the modern Internet to operate and grow. Actually, here the word Internet emerged, meaning “an interconnected network of networks”.

How does it work?

IP protocol works through different rules and resources, like the IP addresses. To connect to the Internet, domains and devices get a unique IP address to be identified and allowed to communicate (exchange data) with other connected devices. 

Data travel across networks separated into pieces (packets). Every piece gets IP information (IP address) attached for routers to read it and send the packet to the correct destination. Once there, the way for those packets to be handle will depend on the kind of protocol (commonly TCP or UDP) combined with the IP to transport them.

IP is a connectionless protocol. All data packets are just addressed, routed, and delivered without existing acknowledgment from the destination to the source. This lack is resolved through the Transmission Control Protocol. 

TCP secures the travel and delivery of data packets across networks through a specific process. To start, a connection between the source and the destination is required, even before the transmission of data begins. This, because TCP is a connection-oriented protocol. To work properly, it needs to guarantee this active connection until the sending and receiving of data get completed.

When the communication begins, TCP takes the sender’s messages and chops them into packets. To protect messages’ integrity, TCP numbers every packet. Then packets are ready to go to the IP layer for being transported. They will be dispatched to travel around different routers and gateways of the network to reach their destination. No matter all the packets are part of the same message, they can have different routes to arrive at the same destination.

Once they all hit their destination, TCP proceeds to re-build the message by putting all their pieces (packets) together again to make a proper delivery. 

This ideal scenario can be affected if networks face issues. Data packets could get lost in transit, duplicated, or disordered. The advantage is TCP’s functionality can detect such problems and fix them. The protocol can ask the lost packets to be re-sent to organize them again in the correct order. In case messages can’t be delivered, this is reported to the sender (source).

As you see, the Internet is a packet-switched network. All data are chopped into packets that are dispatched through lots of different routes simultaneously. When they finally hit their destination, they get re-built by TCP. And IP is in charge of the packets to be sent to the correct destination.

TCP/IP layers

TCP/IP’s most updated model includes the following four layers. All collaborate for the same purpose, the transmission of data.

• Application layer. This is the top layer, and it supplies an interface for applications and network services to communicate. It identifies participants involved in a communication, defines the access to the network’s resources, and the rules for application protocols and transport services interaction. Application layer includes all the higher-level protocols like DNS, HTTP, SSH, FTP, SNMP, SMTP, DHCP, etc.
• Transport layer. It defines the amount of data and the rate for transporting data correctly. It receives messages from the application layer, divides them into pieces, transports them, re-builds them following the proper sequence, and solves possible issues to guarantee their integrity and proper delivery. TCP operates in this layer.
• Internet layer. The internet layer, also known as the IP or network layer (not to be confused with the network access layer), is in charge of sending packets and ensuring that data is transferred as precisely as possible. As it controls the direction and pace of traffic, it is somewhat similar to a traffic controller on a road. Additionally, it supplies the procedural steps and functionalities for transferring data sequences. This layer’s protocols include IPv4, IPv6, ICMP, and ARP.
• Network access layer: The OSI model’s data link layer and physical layer are combined to form the network access layer. It outlines the process through which data is actually transferred over the network. It also covers how hardware components that physically interact with a network, such as twisted-pair copper wire, optical fiber, and coaxial cable, transmit data via optical or electrical means. The network access layer is the bottom layer in the TCP/IP model.

Understanding the TCP Handshake process

The TCP handshake process is the key to establishing a reliable connection between two devices. Known as the “three-way handshake,” this method ensures that both the sender and receiver are ready for communication before any data is transmitted. Here’s how it works step-by-step:

1. SYN (Synchronization): The process begins when the client sends a SYN packet to the server, indicating a request to start communication. This packet also contains an initial sequence number, allowing the client to mark the starting point for data transmission.

What SYN flood attack is?

2. SYN-ACK (Acknowledgment of Synchronization): The server responds with a SYN-ACK packet, acknowledging the client’s request and including its own sequence number. This signals that the server is ready to receive data and has marked its starting point for tracking data segments.
3. ACK (Final Acknowledgment): The client sends an ACK packet back to the server, acknowledging the server’s response. This final step completes the handshake, and a stable connection is established, allowing data exchange to begin.

What is the difference between TCP and IP?

TCP and IP are two different computer network protocols. Each function in the data transmission process distinguishes TCP (Transmission Control Protocol) from IP (Internet Protocol). Using IP, you may find out where data is sent (your device has an IP address). Once that IP address has been discovered, TCP guarantees accurate data delivery. The pair make up the TCP/IP protocol suite.

In other words, TCP sends and receives mail while IP sorts it. Other protocols, such as UDP (User Datagram Protocol), can transfer data within the IP system without the usage of TCP, even though the two protocols are typically regarded as a pair. But for TCP to deliver data, it needs an IP address. So another distinction between IP and TCP is this.

How to find your TCP/IP address?

To find your TCP/IP address, you can use simple methods for both your public and private IP addresses. Your public IP address, which identifies your device on the internet, can be easily found by searching “What is my IP address” in most search engines. This method displays the IP address assigned to your network by your Internet Service Provider (ISP).

For your private IP address, which is used within your local network, the process varies slightly depending on your device:

1. On Windows: Open the Command Prompt and type ipconfig. Your IP address will be listed under the appropriate network adapter as the IPv4 Address.
2. On macOS: Go to System Preferences, select Network, and choose the network you’re connected to. Your IP address will be displayed there.
3. On Linux: Open the Terminal. You can find your IP address by typing ifconfig for older distributions or ip addr for newer ones. Your IP address will be listed under the relevant network interface. 
4. On mobile devices: Go to your Wi-Fi settings. Depending on your device, you may need to tap on the network you’re connected to see details like the IP address.

For TCP ports, determining which ports are being used by your device typically involves more technical steps. You can use network utilities or command-line tools to list active ports. These tools can help you identify which ports are open and in use, which is particularly useful for network troubleshooting or configuring firewall settings.

Remember, knowing your TCP/IP address is crucial for various network tasks, from setting up your home network to troubleshooting connectivity issues.

Are my data packets secure?

The answer is no. Why? When packets are sent between devices, they are highly susceptible to being intercepted by others. So, that’s why it’s better to utilize encryption and stay away from public Wi-Fi networks when transmitting messages that need to remain secret. But unfortunately, this is sometimes not enough, which is why you need to take other actions. Here’s what they are:

1. Use Monitoring service

Systematically monitoring your network for any unusual activity. This reduces the exposure gap you have to cyberattacks. Additionally, TCP monitoring, which is a feature of the Monitoring service, uses a highly specialized protocol to examine connectivity and find communication problems on network machines. As a result, it can quickly identify issues and alert you.

2. VPN

A VPN is a great way to guarantee that your data is securely encrypted and that your packets are safeguarded throughout network traffic. A VPN can be manually configured or purchased. Furthermore, VPN comes with numerous additional advantages. For example, website unblocking, location hiding, and restricting the pages you browse from being seen by your ISP (Internet Service Provider).

3. Employ HTTPS protocols

Hypertext Transfer Protocol Secure (HTTPS), the prefix for encrypted websites, denotes the security of user activity there. Websites that begin with “HTTP” are unable to provide the same level of protection. Secure Sockets Layer (SSL) connections are indicated by the “s” in HTTPS, which stands for secure. Doing this guarantees, the data is encrypted before being delivered to a server. Therefore, to prevent packet sniffing, it is preferable only to visit websites that start with “HTTPS.”

HTTP vs HTTPS: Why every website needs HTTPS today

4. Make use of Private DNS 

Another important way to secure your data is to use Private DNS. Nowadays, using Public DNS has a lot of dangers. With Private DNS, you will be more secure against cyberattacks. Why? Because you can use Transport Layer Security (TLS) and Hypertext Transfer Protocol Secure (HTTPS). These protocols encrypt any DNS queries sent out, and DNS over these protocols is known as DoH (DNS over HTTPS) and DoT (DNS over TLS).

Advantages of TCP/IP

• It allows connecting different kinds of devices.
• It makes possible cross-platform communications among diverse networks. 
• It supports different protocols for routing.
• It offers high possibilities of scalability. You can add networks without causing trouble. 
• It supplies IP addresses to devices for identifying them.
• It’s independent of the operating system.
• It’s an open protocol. No one owns it. Everybody can use it.
• It facilitates reliable communication through data packet retransmission in case of loss, ensuring data integrity.
• It offers robust error detection and correction capabilities, enhancing data transmission reliability.

Disadvantages of TCP/IP

• To replace protocols on TCP/IP is not simple.
• It doesn’t define clearly the concepts of services, protocols, and interfaces. It can be difficult to assign a category to new technologies included in modern networks.
• It works for wide networks. It’s not suitable for small ones (PAN or LAN).
• Susceptible to security vulnerabilities if not properly secured, making encryption and other security measures essential.

TCP vs UDP

There are clear differences between the transmission control protocol (TCP) and User Datagram Protocol (UDP).

• TCP is connection-oriented, while UDP is connectionless. TCP requires an active connection to start and complete the data transmission, while UDP does not.
• TCP can recover lost packets by requiring retransmission. UDP can’t recover them.
• TCP is much slower than UDP because its process involves verification in almost every step. To guarantee the connection is active and the source ready to receive a message, to confirm delivery, etc. UDP only sends, avoiding those confirmation steps.
• TCP protects packets’ integrity efficiently. To protect this is not UDP’s strength. Its mechanism to check integrity (checksum) is less precise.

An Overview of TCP Monitoring vs UDP Monitoring

• TCP delivers ordered messages (by reassembling them based on a numerical sequence). UDP doesn’t offer this function.
• TCP guarantees the data delivery to their recipient. UDP doesn’t. 
• TCP detects and fixes possible errors better. It also supplies confirmation of delivery or reports the problem if it’s not possible to deliver. The UDP’s mechanism for error detection (checksum) is simpler and limited. It doesn’t confirm or inform about the delivery.
• TCP’s speed doesn’t solve latency. UDP really does it.
• TCP doesn’t support broadcast, while UDP really does since it does not require response or confirmation.
• The efficiency of TCP makes it ideal for applications that demand full integrity of data, zero loss (HTTP, FTP, IMAP, SSH, SMTP).
• UDP works very well for applications that require high speed and can afford data loss. Think about real-time applications like live video streaming, voice-over IP or online gaming.

Why does DNS use UDP?

TCP vs HTTP

The Transmission Control Protocol (TCP) and the Hypertext Transfer Protocol (HTTP) also differ between them. 

• TCP is used to set communication or a session between two machines (client and server). In contrast, HTTP is used for accessing data of webpages and accessing content (websites) from a web server. It’s a client-server protocol. Requests begin with the recipient, like a browser.
• TCP is a data transfer protocol. HTTP uses TCP for data transfer.
• TCP uses IP addresses, while HTTP uses hyperlinks, also known as URLs. 
• TCP is connected-oriented, while HTTP is stateless but not sessionless.
• TCP needs authentication (TCP-AO). HTTP does not.
• TCP process involves a three-way handshake, and this takes some time. HTTP is one-way communication. TCP is slower than HTTP.
• TCP uses different ports (80, 8000, 8080, etc.). HTTP usually uses the 80 port.

Conclusion

There are different protocols, and understanding their potential is basic to choose the one that better suits your network’s needs. In many cases, these technologies compliment others. TCP, independently and combined with IP, is an efficient protocol with useful functionality for the Internet and networks in general. Try them and get the best out of them!

The post TCP (Transmission Control Protocol) – What is it, and how does it work?  appeared first on ClouDNS Blog.

What is a flood attack?

A flood attack, often a form of Distributed Denial of Service (DDoS) attack, aims to overwhelm a system with superfluous requests, thus preventing legitimate requests from being fulfilled. The primary objective is to make the target service unavailable, either by consuming all its resources or crashing it altogether. Flood attacks exploit the limitations of a network’s bandwidth, memory, and processing power. By sending an excessive number of requests, they can exhaust these resources rapidly, causing severe disruptions. Attackers often use botnets, a network of compromised devices, to generate the enormous volume of traffic required for such attacks, making it harder to trace and block the sources.

How does it work?

A flood attack works by sending a massive volume of traffic to a targeted server, service, or network. This traffic often appears to be from legitimate users, which makes it challenging to distinguish and filter out. The target system gets overwhelmed by this surge in requests, which eventually leads to its degradation or shutdown. Flood attacks can be executed through various protocols and methods, such as TCP, UDP, ICMP, and HTTP, each exploiting different aspects of the network’s communication process. Advanced flood attacks may use randomization techniques to avoid detection and mitigation efforts, making them more sophisticated and harder to counter.

Why is flood attack dangerous?

• Disruption of service: The most immediate impact is the service disruption. Websites may become unavailable, networks may slow down, and businesses may experience downtime.
• Financial impacts: With downtime comes lost revenue. Especially for businesses that rely heavily on online services, a few minutes of inaccessibility can translate to significant financial losses.
• Damage to reputation: Continuous attacks can tarnish a company’s reputation, causing loss of customer trust and loyalty.
• Resource consumption: An immense amount of resources, both human and technological, need to be diverted to handle the aftermath of such attacks.
• Diversion: Sometimes, attackers use flood attacks as a smokescreen, diverting attention from a more covert breach or intrusion.

How to mitigate it?

• Monitoring: Continuous monitoring of network traffic can help in early detection of unusual traffic spikes, which may indicate a flood attack. Tools like intrusion detection systems (IDS) can be invaluable.
• DDoS Protection: DDoS protection services can help mitigate the effects of a flood attack. These services often use a combination of traffic filtering, rate limiting, and other tactics to ensure only legitimate traffic reaches the target. 
• Secondary DNS: If the primary DNS server becomes overwhelmed due to a flood attack, the secondary DNS server can continue to resolve domain names, ensuring that services remain accessible to legitimate users.
• Firewalls and Routers: Properly configured firewalls and routers can help filter out malicious traffic.
  Router vs firewall
• TTL Analysis: Investigate the TTL values on incoming packets. Abnormal TTLs can indicate potential malicious traffic.
• IP Blocklisting: Identify and block IPs that show malicious activity. This prevents them from accessing your systems further.
  Whitelisting vs Blacklisting

Types of flood attack

DNS Flood Attack

A DNS flood attack specifically targets the Domain Name System (DNS) servers. The DNS is the internet’s phonebook, translating human-friendly URLs (like “example.com“) into IP addresses that computers use to identify each other on the network (like “1.2.3.4”). In a DNS flood attack, attackers send a high volume of DNS lookup requests, usually using fake IP addresses. This causes the DNS servers to try and resolve each request, leading to an overwhelming number of processes. This congestion ensures that genuine requests from real users either get significantly delayed or ignored altogether. If an attacker successfully disrupts a DNS server, it can make a whole swath of websites or online services inaccessible.

SYN Flood Attack

To understand a SYN flood attack, one must first grasp the “three-way handshake” process used to establish a TCP connection. The sequence is SYN, SYN-ACK, and ACK. In a SYN flood attack, the attacker sends a rapid succession of SYN requests but either does not respond to the SYN-ACK replies or sends them from spoofed IP addresses. The target system will keep these connections open, waiting for the final ACK that never comes. This can consume all available slots for new connections, effectively shutting out legitimate users.

HTTP Flood Attack

HTTP flood attacks take advantage of the HTTP protocol that web services operate on. In this attack, a massive number of HTTP requests are sent to an application. Unlike other flood attacks, the traffic sent looks legitimate. The requests can be either valid URL routes or a mixture with invalid ones, making them harder to detect. Because the requests look so much like typical user traffic, they’re particularly difficult to filter out. This method can exhaust server resources and cause legitimate requests to time out or receive delayed responses.

ICMP (Ping) Flood Attack

ICMP, or Internet Control Message Protocol, is a network protocol used by network devices to send error messages. The “ping” tool uses ICMP to test the availability of network hosts. In a Ping flood attack, attackers inundate the target with ICMP Echo Request (or ‘ping’) packets. The target then tries to respond to each of these requests with an Echo Reply. If the attack is voluminous enough, the target system’s bandwidth or processing capabilities may get overwhelmed, causing a denial of service.

Suggeted page: The function of ICMP Ping monitoring

UDP Flood

User Datagram Protocol (UDP) is a sessionless networking protocol. In a UDP flood attack, the attacker sends many UDP packets, often with spoofed sender information, to random ports on a victim’s system. The victim’s system will try to find the application associated with these packets but will not find any. As a result, the system will often reply with an ICMP ‘Destination Unreachable’ packet. This process can saturate the system’s resources and bandwidth, preventing it from processing legitimate requests.

Impact of Flood attacks on different industries

Flood attacks can have devastating effects across various industries, each facing unique challenges and potential damages:

E-commerce:

E-commerce platforms rely heavily on their websites for sales and customer interaction. A flood attack can cause significant downtime, leading to lost sales, decreased customer trust, and potential long-term damage to the brand’s reputation. Additionally, the costs associated with mitigating the attack and enhancing security measures can be substantial.

Suggest: Global Reach, Local Touch: The Role of GeoDNS in eCommerce Expansion

Finance:

In the finance sector, the availability and integrity of online services are critical. Flood attacks can disrupt online banking, trading platforms, and payment processing systems. This not only affects customer transactions but can also lead to compliance issues and regulatory scrutiny. The financial losses and impact on customer confidence can be severe.

Healthcare:

Healthcare providers use online systems for patient management, medical records, and telemedicine. A flood attack can interrupt these services, potentially putting patient health at risk. Delayed access to medical records and appointment scheduling can cause significant operational disruptions and affect the quality of care provided.

Gaming:

The gaming industry is a frequent target of flood attacks, especially during major events or game launches. These attacks can disrupt gameplay, causing frustration among users and leading to a loss of revenue for gaming companies. The competitive nature of online gaming also means that downtime can significantly impact player engagement and retention.

Conclusion

Flood attacks are among the oldest tools in a hacker’s arsenal, but they remain effective. As the digital landscape grows and evolves, so do the methods attackers employ. Regularly updating security infrastructure, staying informed about emerging threats, and employing a proactive defense strategy can go a long way in keeping systems secure and operational.

The post Flood Attack: Prevention and Protection appeared first on ClouDNS Blog.

It helps determine if the transferred data is reaching its target destination on time. For that reason, ICMP is an essential element when it comes to the error reporting process and testing. However, it often gets utilized in DDoS (Distributed Denial-of-Service) attacks.

History of ICMP

The ICMP protocol was conceived as a vital component of the Internet Protocol Suite, introduced in 1981 with RFC 792. Its origins can be traced back to the early days of the internet when the need for a diagnostic and error-reporting tool was identified. Over the years, ICMP has experienced several refinements, with additional message types being introduced. Its fundamental purpose of providing feedback about issues related to datagram processing has remained consistent throughout, making it an indispensable tool for network diagnostics.

What is ICMP protocol used for?

The ICMP protocol could be used in several different ways. They are the following:

The main purpose of ICMP is to report errors

Let’s say we have two different devices that connect via the Internet. Yet, an unexpected issue appeared, and the data from the sending device did not arrive correctly at the receiving device. In such types of unpleasant situations, ICMP is able to help. For instance, the problem is occurring because the packets of data are too large, and the router is not capable of handling them. Therefore, the router is going to discard the data packets and send an ICMP message to the sender. That way, it informs the sending device of the issue.

ICMP is commonly used as a diagnostic tool

It is used to help determine the performance of a network. The two popular utilities, Traceroute and Ping, operate and use it. They both send messages regarding whether data was successfully transmitted.

• The Traceroute command is helpful for displaying and making it easy to understand the routing path between two different Internet devices. It shows the actual physical path of connected routers that handle and pass the request until it reaches its target destination. Each travel from one router to another is called a “hop.” The Traceroute command also reveals to you how much time it took for each hop along the way. Such information is extremely useful for figuring out which network points along the route are causing delays.
• The Ping command is similar, yet a little bit more simple. It tests the speed of the connection between two different points, and in the report, you can see precisely how long it takes a packet of data to reach its target and return to the sender’s device. Despite the fact that the Ping command does not supply additional data about routing or hops, it is still an extremely beneficial tool for estimating the latency between two points. The ICMP echo-request and echo-reply messages are implemented during the ping process.

Cybercriminals utilize it too

Their goal is to disturb the normal network performance. They initiate different attacks, such as an ICMP flood, a Smurf attack, and a Ping of death attack. Attackers are determined to overwhelm the victim and make the standard functionality not possible.

How does it work?

Internet Control Message Protocol stands as one of the leading protocols of the IP suite. Yet, it is not associated with any transport layer protocol, for instance, Transmission Control Protocol (TCP) or User Datagram Protocol (UDP).

ICMP is one of the connectionless protocols, which means that a sending device is not required to initiate a connection with the receiving party before transmitting the data. That is why it differs from TCP, for instance, where a connection between the two devices is a mandatory requirement. Only when both devices are ready through a TCP handshake, a message could be sent.

All ICMP messages are sent as datagrams and include an IP header that holds the ICMP data. Each datagram is a self-contained, independent entity of data. Picture it as a packet holding a portion of a larger message across the network. ICMP packets are IP packets with ICMP in the IP data part. ICMP messages also include the complete IP header from the original message. That way, the target system understands which precise packet failed. 

ICMP Packet Format

ICMP is designed to be used within IP packets. When an ICMP message is sent, it is encapsulated within an IP packet, and the ICMP header follows the IP header within that packet.

In the ICMP packet format, the first 32 bits of the packet are divided into three fields:

Type (8-bit): The initial 8 bits of the packet specify the message type, providing a brief description so the receiving network knows the kind of message it is receiving and how to respond. Common message types include:

• Type 0: Echo reply
• Type 3: Destination unreachable
• Type 5: Redirect Message
• Type 8: Echo Request
• Type 11: Time Exceeded
• Type 12: Parameter problem

Code (8-bit): The next 8 bits are for the code field, which provides additional information about the error message and its type.

Checksum (16-bit): The last 16 bits are for the checksum field, which checks the number of bits in the complete message to ensure that all data is delivered correctly.

Extended Header (32-bit): The next 32 bits of the ICMP header are the Extended Header, which points out issues in the IP message. Byte locations are identified by the pointer which causes the problematic message. The receiving device uses this information to pinpoint the issue.

Data/Payload: The final part of the ICMP packet is the Data or Payload, which is of variable length. In IPv4, the payload includes up to 576 bytes, while in IPv6, it includes up to 1280 bytes.

Types and codes in ICMP

ICMP messages are distinguished by their type and, in some cases, a code to further specify the nature of the message. There are numerous types, each serving a unique purpose. A few common types include:

• Echo Reply (Type 0): A response to an echo request, commonly used in ping.
• Destination Unreachable (Type 3): Indicates that the destination is unreachable for some reason. Various codes further specify the reason, such as network unreachable (Code 0), host unreachable (Code 1), or protocol unreachable (Code 2).
• Redirect (Type 5): Informs the host to send its packets on an alternative route. The accompanying codes provide more details, like redirect for the network (Code 0) or redirect for the host (Code 1).
• Time Exceeded (Type 11): Generated when a packet takes too long to transit a network or when reassembly time is exceeded.

These are just a few examples, and there are many other types and codes in the ICMP specification that serve various purposes.

Configuring ICMP on routers and firewalls

Configuring ICMP settings on routers and firewalls is essential to either allow ICMP traffic, prioritize it, or block it to enhance security. Here’s a brief guide:

On Routers:

1. Access the router’s admin panel, usually through a web interface or command line.
2. Navigate to the advanced settings or firewall settings.
3. Look for an option related to ICMP or ‘Ping Request’ and either enable or disable it as required.

On Firewalls:

1. Open the firewall management interface.
2. Search for a rule or setting related to ICMP traffic.
3. Modify the rule to allow, block, or prioritize ICMP traffic based on your needs.

It’s crucial to consult the router or firewall’s documentation or seek expert advice, as incorrect configurations might result in network vulnerabilities or communication problems.

Router vs firewall, can you guess which is better?

ICMP Port?

As we mentioned earlier, the Internet Control Message Protocol is a part of the Internet protocol suite, also known as the TCP/IP protocol suite. That means it relates only to the Internet Layer. Port numbers are only found in the Transport Layer, which is the layer above.

Although Internet Control Message Protocol does not implement the concept of ports like TCP and UDP, it utilizes types and codes. Typically employed ICMP types are echo request and echo reply (used for Ping) and TTL (time-to-live) exceeded in transit (used for Traceroute).

What is ICMP Ping?

The ICMP echo request and the ICMP echo reply messages are also known as ping messages. Ping command is a beneficial troubleshooting tool that system administrators use to test for connectivity between network devices manually. They also use it for examining for network delay and loss packets.

ICMP Ping is especially useful for performing Ping Monitoring. It works by frequently pinging a precise device. This type of check sends an ICMP echo request to a specific server or device on the network, and the device instantly answers with an ICMP echo reply. That means the connection is successful, and the target server or device is up and running without any issues. 

In case the ping time, which is measured in milliseconds (ms), is prolonged, that is a sure sign of some network issues. 

ICMP vs TCP

The Internet Control Message Protocol, or ICMP, has a completely different function compared to TCP (Transmission Control Protocol). Unlike it, ICMP is not a standard data packet protocol. Moreover, it is a control protocol, and it is not designed to deal with application data. Instead, it is used for inter-device communication, carrying everything from redirect instructions to timestamps for synchronization between devices. It is important to remember that ICMP is not a transport protocol that sends data between different devices.

On the other hand, TCP (Transmission Control Protocol) is a transport protocol, which means it is implemented to pass the actual data. It is a very popular protocol, thanks to its reliability. TCP transfers the data packets in a precise order and guarantees their proper delivery and error correction. Therefore, the Transmission Control Protocol finds its place in many operations, including email and file transfers. It is the preferred choice when we want to ensure ordered, error-free data, and speed is not the top priority.

Suggested page: What TCP monitoring is?

ICMP in IPv6 (ICMPv6)

With the growing adoption of IPv6, ICMP has also evolved to cater to the needs of the newer IP protocol. ICMPv6, introduced with RFC 4443, is more than just an adaptation; it incorporates various features and functionalities tailored for IPv6. For instance:

• Neighbor Discovery Protocol (NDP): ICMPv6 includes NDP, replacing the ARP (Address Resolution Protocol) used in IPv4, facilitating the discovery of neighboring devices.
• Router Solicitation and Advertisement: ICMPv6 aids in the discovery of routers in a network and can solicit advertisements from them.
• Enhanced Error Reporting: ICMPv6 offers more detailed feedback, facilitating improved troubleshooting in IPv6 networks.

As the internet continues its transition from IPv4 to IPv6, the importance and relevance of ICMPv6 will only grow, making it vital for network professionals to familiarize themselves with its intricacies.

Suggested article: IPv4 vs IPv6 and where did IPv5 go?

How is ICMP used in DDoS attacks?

DDoS (Distributed Denial-of-Service) attacks are extremely popular cyber threats. They are initiated with the main goal to overwhelm the victim’s device, server, or network. As a result, the attack prevents regular users from reaching the victim’s services. There are several ways an attacker can utilize ICMP to execute these attacks, including the following:

• ICMP flood attack

ICMP flood, also commonly called Ping flood attack, attempts to overwhelm the target device with ICMP echo request packets. That way, the victim device is required to process and respond to each echo request with echo reply messages. That consumes all of the existing computing resources of the target and prevents legitimate users from receiving service.

The basics of flood attacks

• Ping of death attack

The Ping of Death attack appears when a cybercriminal sends a ping larger than the maximum permitted size for a packet to a victim device. As a result, the device crashes. The large packet is fragmented on its way to the victim. However, when the device reassembles it into its original, the size exceeds the limit and causes a buffer overflow. 

The Ping of Death is considered a historical attack that does not appear anymore. Yet, that is not completely true. Operating systems and networking equipment that is more aged could still become a victim of it.

• Smurf attack

The Smurf attack is another common threat where the cybercriminal sends an ICMP packet with a spoofed source IP address. The network equipment responds to the packet and sends the replies to the spoofed IP, which floods the target with large amounts of ICMP packets. 

Just like the Ping of Death attack, the Smurf attack should not be disregarded. Unfortunately, in a lot of different companies and organizations, the equipment is a bit aged, and the threat is real!

Conclusion

The ICMP (Internet Control Message Protocol) is an incredible network layer protocol that allows devices to report errors and improve their communication. Moreover, it is a great tool for network diagnosis. It is not a surprise that a lot of administrators use it daily for a better understanding of their network with the popular utilities Ping and Traceroute. Even more beneficial is the Ping monitoring, which completes regular checks. Lastly, keep in mind to take proper supervision of your network, so it stays protected from DDoS attacks that utilize the protocol for malicious purposes.

The post What is ICMP (Internet Control Message Protocol)? appeared first on ClouDNS Blog.

Understanding DNS

The Domain Name System, or shortly DNS, is the internet’s address book, responsible for translating human-friendly domain names (like www.domain.net) into the numerical IP addresses (like 123.45.6.7) that computers use to communicate with each other. It acts as a distributed database, allowing quick and efficient DNS resolution of domain names to IP addresses (IPv4 and IPv6).

Additionally, DNS is a part of the application layer. As you probably know, all application layer protocols require the use of a transport layer protocol like UDP (User Datagram Protocol) and TCP (Transmission Control Protocol). In the case of DNS, it prefers to utilize the not-so-reliable UDP protocol in most cases. Yet, occasionally it uses the more reliable TCP protocol. 

Let’s dive deep and explain more about these protocols and when and why the Domain Name System puts them in use.

DNS using UDP and TCP

Both UDP and TCP are protocols used to send packets of data over the internet. They do that on top of the IP protocol, which means that they direct the packets to IP addresses. They are treated very similar on their way from the users’ computers, through the routers and all the way to the end destination.

DNS and TCP

TCP, also known as Transmission Control Protocol, is a widely used transport layer protocol. When you make a request for a website from your browser, it will most probably use exactly TCP protocol to send the data packets to the server. For every request you send (every action you take on the web page like click, sign in, etc.) you will receive TCP packets back.
TCP is orientated to the reliability. All the data sent over TCP is tracked, and no data gets corrupted or lost on the way. The protocol numbers the packets and does error checking by pushing the receiver to confirm that it got the data.

Here are some cases in which DNS utilizes TCP (Transmission Control Protocol):

• Zone Transfer: When a DNS server needs to transfer a complete DNS zone to another server, it typically uses TCP. This ensures the reliable delivery of larger data.
• Large DNS Responses: TCP is used when DNS responses exceed the maximum size supported by UDP, which is 65,535 bytes. This can happen with DNSSEC or large resource records.
• DNS over TCP (DoT) and DNS over TLS (DoT): For enhanced security, DNS can be encrypted using TCP-based protocols like DoT and DoT, protecting against malicious attempts.
• Firewall and Network Restrictions: When firewalls or network policies block UDP, DNS queries and responses are transmitted over TCP.

Learn more about TCP (Transmission Control Protocol) !

DNS and UDP

The UDP protocol is all about speed. All those checking of the packets slow down the communication and create latency. By using UDP, the receivers don’t need to confirm the packets; the sender just continues sending without wasting extra time to receive feedback. In this communication, the receivers lose some of the packets, but it doesn’t stop the communication. This makes it perfect for live streaming or online games, even if the connection stops for a bit and the screens of the receivers freeze, in a moment they will receive the next packet, and everything will continue.

DNS primarily uses UDP (User Datagram Protocol) for most of its operations. UDP is chosen for its speed, efficiency, and suitability for small, time-sensitive DNS queries and responses. UDP is used in the following cases:

• Regular DNS queries: When you enter a web address, UDP is used to send the query from your device to a DNS server.
• DNS responses: The DNS server sends the response, including the IP address, back to your device using UDP packets.
• Caching: DNS servers often cache previously resolved queries, allowing for faster responses using UDP without querying authoritative servers again.
• Small data transfers: DNS queries and responses are typically small, fitting well within UDP’s maximum packet size of 65,535 bytes.
• Stateless communication: DNS operates on a stateless model, and UDP’s stateless nature enables the efficient processing of multiple requests together.

UDP explained in details

Why does DNS prefer UDP?

As you just read, the UDP is unreliable but a lot faster than TCP, but don’t panic just yet. DNS requests are very tiny, so they have no problems fitting into the UDP segments.
It doesn’t use a time-consuming three-way hand-shake procedure to start the data transfer like TCP does. The UDP just transmits the data and saves plenty of time.
UDP can support many more clients at the same time thanks to the lack of connection state. The TCP has Receive and Send buffers, Sequence and Acknowledge Number Parameters and congestion-control parameters.
Don’t think it is so dangerous using UDP, you can add extra protection on the application layer. An application can use it and it can be reliable by using timeouts and resend at the application layer.

How does Domain Name System work?

In the DNS world, we are trying to cut the resolving time as much as possible. Seconds is an eternity, we want to reduce the time to just a few milliseconds. TCP is more secure, but it just can’t keep up with the UDP, and about protection, there are extra ways of adding it. So, in the end, you get them both – speed and protection.

Advantages and Disadvantages of Using UDP for DNS

UDP is widely used for DNS operations. Below are some of the advantages and disadvantages of using UDP for DNS.

Advantages:

• Speed and Efficiency: UDP is faster than TCP because it is connectionless, which means it does not establish a connection before sending data. This makes DNS queries quicker and more efficient, crucial for the large volume of DNS requests.
• Lower Overhead: UDP has less overhead compared to TCP, as it does not perform error-checking and connection management. This results in faster data transmission and lower latency.
• Simplicity: UDP has a simple protocol structure that allows easier and faster processing of DNS queries and responses.

Disadvantages:

• Lack of Reliability: UDP does not guarantee the delivery of packets, which can lead to packet loss. This lack of reliability can affect the accuracy of responses.
• No Error Correction: Since UDP does not include mechanisms for error correction, any lost or corrupted packets are not retransmitted. Additional mechanisms to handle these issues may be needed.
• Security Concerns: Because it is stateless, it is more exposed to spoofing and other types of attacks, requiring additional security measures.

Despite these challenges, the efficiency of UDP makes it a preferred choice in DNS operations. Its ability to quickly resolve numerous requests with minimal overhead outweighs the potential drawbacks, making it suitable for the high demands of DNS queries.

Conclusion

In conclusion, DNS uses UDP due to its speed, efficiency, and suitability for most DNS operations. UDP allows fast DNS resolution of domain names, quick delivery of DNS queries and responses, and efficient processing of small, time-sensitive data transfers. While TCP is employed in specific cases such as zone transfers, larger responses, and encrypted communication, UDP remains the preferred choice for its lightweight nature and low resource usage. The utilization of UDP in DNS ensures the smooth functioning of the internet, connecting users to their desired websites and services with speed and efficiency.

The post Why does DNS use UDP? appeared first on ClouDNS Blog.

What is FTP?

FTP, or File Transfer Protocol, is a standard network protocol used for transferring files between a client and a server. It dates back to the early days of the Internet and remains widely used today. It operates on the client-server model, where one computer (the client) establishes a connection with another computer (the server) to exchange files. FTP supports two modes: active mode and passive mode, which determine how data connections are established. It uses separate control and data channels, making it ideal for large file transfers, directory synchronization, and remote file management.

FTP is an old protocol, still from the age without a graphical interface. Abhay Bhushan first published it on 16.04.1971. You can access it through the command-line, or through a modern graphical interface. There are options that integrate it inside programs for web admins.
FTP transfer files by using the TCP. It needs to establish two connections, the data connection on port 20 and the second is control information on port 21.
You can use FTP if you are trying to install WordPress or another CMS on your web hosting. You can also use it to back up your website and download a copy of it to your computer. Less and less, people are using it to transfer files between them. The cloud solutions are making FTP absolute.

What is HTTP?

HTTP, or Hypertext Transfer Protocol, is the foundation of the World Wide Web. It defines how web browsers and web servers communicate and exchange information. HTTP functions through a request-response model, where a client sends a request to a server, and the server responds with the requested data. It operates on the application layer of the TCP/IP protocol suite, making it versatile for various web-related tasks, including browsing, data retrieval, and API interactions.

The creator of it is the famous father of the internet – Tim Berners-Lee. He developed it back in 1989 in CERN. Just like the FTP, HTTP also uses a client-server model. When you use your web browser and type an URL, you will use HTTP over TCP/IP (port 80). That way, you send a HTTP request to get the desired website (text, images, videos and all other kinds of content). The web server will give you back the answer with the desired web page (all files on it).

FTP vs HTTP

Both FTP and HTTP are part of the application layer that combines communication protocols and interface methods. Here we will see how they are different.

• You can use HTTP to view websites and the FTP just for transferring files.
• The client for HTTP is the browser (Chrome, Opera, etc.) and for the FTP is the command-line.
• Both can be used to admin a website, but HTTP is more popular. Just in some cases, the FTP can be more appropriate.
• It is believed that FTP is more efficient for larger files, while HTTP is better for smaller files.
• FTP doesn’t send meta-data, just binary and the HTTP uses pipelining to organize the transfer of multiple files.

Here is a comparison table that illustrates the differences between FTP and HTTP:

Suggested: SFTP vs HTTPS

Choosing the Right Protocol

The choice between FTP and HTTP largely depends on your specific requirements. Additionally, when deciding, it’s important to understand the specific advantages of each protocol.

FTP might be the optimal choice if your primary objective is to transfer files, especially large ones, access remote servers, or perform backups. It handles larger data sizes more efficiently and allows for the resume of transfers in case of interruption. It is ideal for situations like server migrations, backing up large databases, or transferring high volumes of media files.

On the other hand, HTTP is more suitable if you primarily engage in everyday web tasks such as web browsing, downloading smaller files, or interacting with web applications. HTTP is stateless by nature, making it efficient for these types of operations where each new connection doesn’t need knowledge of previous interactions. Additionally, HTTP’s ability to work seamlessly with modern web technologies and its compatibility with various data formats makes it the better choice for web-based applications.

In summary, choose FTP when dealing with extensive file transfers or when working within a network that you control for tasks like backups and server maintenance. Opt for HTTP when you need to interact with web pages or services, especially when performance and compatibility with web standards are critical. That way, you will ensure you leverage the strengths of each protocol based on your specific needs.

Conclusion

FTP vs HTTP is not really a question anymore. The internet has adopted the HTTP standard, and there is going back. FTP is not a bad protocol, but HTTP can do almost everything it can. And the safer version HTTPS is the new must on any page. FTP is starting to have problems with some firewalls because of the port that it is using (some firewalls allow just the ports for HTTP and HTTPS). FTP will soon disappear, and it is ok to let it go.

The post FTP vs HTTP: Understanding the Key Differences appeared first on ClouDNS Blog.

What is User Datagram Protocol?

The short acronym UDP stands for User Datagram Protocol, and it is a communication protocol applied across the Internet. It sets low-latency and loss tolerating connections between the different applications.

UDP offers fast communication due to the fact it allows data transfer before the receiving party provides an agreement. Therefore, UDP is highly valuable in communications that require speed and are considered time-sensitive. For example, Voice over IP (VoIP), Domain Name System (DNS) lookup, and video or audio playback.

Yet, this protocol is prone to data packet loss during travel from the source to the target destination. As a result, it could create some difficulties with the data transfer and makes it easy for cybercriminals to execute a Distributed Denial-of-Service (DDoS) attack.

History of UDP

User Datagram Protocol (UDP) emerged in the 1980s as part of the TCP/IP suite. It was initially developed for the ARPANET project, also known as the precursor to today’s internet. Created by David P. Reed and others, UDP was designed for simplicity and efficiency in transmitting datagrams, making it ideal for applications where speed and low overhead are priorities.

Unlike TCP, UDP does not guarantee delivery or order of packets, nor does it manage connections. This lack of reliability allows UDP to be lightweight, making it suitable for real-time applications like video streaming, online gaming, and voice-over IP (VoIP).

User Datagram Protocol gained fame due to its use in early internet protocols and applications, including DNS (Domain Name System) and DHCP (Dynamic Host Configuration Protocol). Nowadays, it continues to be widely used in various networked applications where low latency and reduced overhead are critical.

Despite its simplicity, UDP’s lack of error correction and flow control means it’s vulnerable to packet loss and out-of-order delivery. However, its efficiency and speed make it necessary in many networking scenarios, complementing TCP’s reliability with a lightweight alternative for specific use cases.

How does it work?

UDP (User Datagram Protocol) acts in a simple way by transferring data between two devices in a network. It transmits packets (datagrams) straight to the target device without setting a connection, specifying the packets’ order, or examining if they are delivered as arranged. 

Compared to TCP (Transmission Control Protocol), UDP provides more speed, yet it is not so reliable. 

TCP communication involves a process known as a “handshake,” which establishes the connection. In addition, only when it is completed the transfer of data packets could happen.

On the other hand, the UDP connection is not including this “handshake” process which means one device simply starts sending the information to the receiving one. Additionally, UDP communications do not include details about the order or confirmation for the arrival of the data. It is exactly the opposite when it comes to TCP.

Based on these characteristics, UDP has the ability to transfer data packets a lot faster than TCP.

The downside of a UDP connection is the loss of packets during the transit, which is not going to be resent as they are in TCP connections. Therefore, when applications implement UDP, they should be able to tolerate losses, duplications, or errors.

TCP Monitoring vs. UDP Monitoring

UDP header

UDP (User Datagram Protocol) operates with headers. It uses them for packaging the message data to be sent over the network. Each UDP header includes several parameters, also known as fields, which are determined by the technical specifications of the protocol.

The UDP (User Datagram Protocol) header contains four main fields. Each of them is 2 bytes. The UDP header has the following fields:

• Source port – It is 16-bit data that specifies the precise port which is going to send the packet. In case the target device doesn’t need to reply to the sender, this field could be set to zero.
• Destination port – It is 16-bit data that serves to specify application-level service on the target device, meaning the port of the device receiving the data. It could be between 0 and 65,535.
• Length – It defines the entire number of bytes, including the UDP header and the UDP data packets for transfer. The precise limit for the UDP length field is defined with the underlying IP protocol utilized to send the data.
• Checksum – It is a 16-bits field, an optional field. The checksum gives the ability for the receiving device to confirm the integrity of the packet header and payload. It is an optional field, meaning if the application wants the checksum or not. In case it doesn’t want the checksum, then all of the 16 bits are zero. In UDP, the checksum field is used for the header and data part. In IP, the checksum field is used only for the header field. It is optional in IPv4, yet it is required in IPv6.

Applications relying on UDP

Gaming, voice, and video

The User Datagram Protocol is a great choice for various different network applications that require minimum latency, like gaming, voice, and also video communications. Services like these will not lower their quality if some of the data packets are lost during the transfer. Yet, despite the lost packets, there is a chance to implement techniques for further error correction and improvement of the audio and video quality. 

Domain Name System Lookups

DNS queries are small and simple requests which receive basic and straightforward answers. A device initiates a DNS query to the DNS servers for receiving essential information about a domain, like the IP address (IPv4 or IPv6). The process is on hold until the DNS query receives its reply. Due to the fact that TCP uses a three-way handshake procedure, it means the request is probably going to be answered very slowly. As a result, it will affect the performance in a negative way. For that reason, DNS queries rely on UDP for quick answers.

Why does DNS use UDP?

Multicasting

Another way for implementing UDP (User Datagram Protocol) is for multicasting. That is based on the fact it supports packet switching. Moreover, this network protocol could also be implemented for additional routing update protocols, for instance, Routing Information Protocol (RIP).

UDP vs. TCP – what are the differences?

Let’s explain a little bit more about what are the main differences between these two protocols:

• Type of protocol

Both TCP and UDP are transport layer protocols. However, there is a main contrast between them. TCP is a connection-oriented protocol. On the other side, UDP is a connectionless protocol. So, simply TCP needs to establish the connection before the communication, while UDP does not need to ensure that the two devices have a connection.

• Reliability

TCP is considered a reliable protocol based on the fact it ensures the delivery of the data packets. It involves an acknowledgment mechanism, in which the sender gets the acknowledgment from the receiver and examines if it is positive or negative. In case it is positive, the data has been delivered successfully. If it is negative, TCP is going to resend the data.

UDP is considered an unreliable protocol based on the fact it does not provide any guarantee that the delivery of the data has been successful.

• Flow Control

TCP involves a flow control mechanism. It makes sure that an extensive number of packets are not sent to the target device simultaneously. On the other hand, UDP does not implement this flow control mechanism at all.

• Ordering

TCP operates with ordering and sequencing techniques. That way, it guarantees that the data packets are going to be delivered in the absolutely exact order in which they were sent. On the other side, UDP does not involve any ordering and sequencing techniques. That means the data could be transferred in any order.

• Speed

As we mentioned, the first step for TCP is to build the connection between the two devices. Additionally, it completes a check for errors and makes sure that the transmission of the data packets is successful. On the other hand, UDP does not build a connection or ensure the transmission. For that reason, UDP is way faster than TCP.

• Flow of data

When we speak about TCP, it offers the full-duplex service. That means the information is able to flow in both directions. Additionally, when we take a look at UDP, it is more fitting for the unidirectional flow of data.

Is UDP secure?

UDP (User Datagram Protocol) serves a great purpose for applications that tolerate packet loss. That is not an issue. Yet, based on the fact that UDP is a connectionless protocol and it does not implement a “handshake” procedure provides an opportunity for cybercriminals. They take advantage of that by flooding their victim with UDP traffic. Attackers do not need to establish a connection and receive permission for initiating such a DDoS attack.

Usually, the UDP flood attack involves sending a massive amount of UDP datagrams to different ports on the victim’s device. That causes the victim to answer with the same amount of ICMP packets indicating that these ports are unreachable. As a result, the victim’s resources are exhausted, and the DDoS attack is completed.

What is flood attack?

Thankfully there are different ways to protect your device, network, server from such malicious attempts. 

• You can limit the response rate of ICMP packets. However, you should know that this could filter out legitimate packets too.

Suggested page: Explanation of ICMP Ping traffic monitoring

• A robust network of many servers (such as Anycast DNS) is a great way to prevent a single server from being drowned with malicious requests.
• Especially for your DNS network, it is a great approach to implement DDoS protection.

Advantages and Disadvantages of UDP

By understanding the main advantages and disadvantages of User Datagram Protocol, you can determine if it is the right protocol for your application. So, let’s take a closer look at what this interesting protocol can offer. 

Advantages of UDP

The User Datagram Protocol provides several benefits, which are the following:

• Fast: It does not require the establishment of a connection before transmitting data, which makes it faster than TCP.’
  Suggested page: Explanation of TCP monitoring
• More efficient: UDP is a lightweight protocol that requires less overhead than TCP.
• Suitable for real-time applications: User Datagram Protocol is ideal for real-time applications, such as online gaming, video conferencing, and live streaming, where speed is more important than reliability.

Disadvantages of UDP

The main drawbacks of the User Datagram Protocol include the following:

• No reliability: It does not guarantee the delivery of packets or guarantee that packets will arrive in order.
• No congestion control: UDP does not have congestion control mechanisms, which means that it can flood a network with packets if not used carefully.
• Limited use cases: User Datagram Protocol is not suitable for applications that require reliable data transmissions, such as file transfers, email, or web browsing.

Suggestes article: Secure File Transfer Protocol (SFTP) Explained

UDP monitoring from ClouDNS – What is it and how to use it?

UDP monitoring is a type of network monitoring that involves scanning a selected UDP port number on a given IP address to check the availability of a service or application. Suppose the monitoring system is unable to establish a connection with the selected port. In that case, it marks the check as DOWN, indicating that the service is unavailable or experiencing issues. UDP monitoring is extremely helpful for identifying potential network problems or service disruptions before they affect end users. In addition, it allows network administrators to quickly diagnose and resolve issues, ensuring that critical services are available and performing optimally.

Conclusion

For sure, the development of UDP (User Datagram Protocol) is revolutionary. It allows fast delivery, which is highly valuable for a number of applications. UDP finds its purpose in many services despite the fact it has some downsides, mainly in DNS, video streaming, and gaming.

The post UDP (User Datagram Protocol) explained in details appeared first on ClouDNS Blog.

Introduction to TCP and UDP

In the digital communication world, two primary protocols govern data transmission over the internet: TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). TCP is renowned for its reliability, establishing a connection before data transfer to ensure all packets are received correctly and in order. This makes it ideal for applications where data integrity is paramount, such as web browsing, email, and secure transactions. On the other hand, UDP offers a connectionless communication model, prioritizing speed and efficiency over reliability. This makes it suitable for applications where fast data transmission is crucial, even at the risk of occasional data loss, such as streaming services, online gaming, and VoIP calls.

Understanding TCP Monitoring

TCP monitoring is a method to ensure that services requiring reliable data transmission are always available and performing optimally. It serves as a diagnostic tool to identify issues in network communication and application performance.

How It Works

TCP monitoring involves scrutinizing the state of TCP connections and the performance of applications using TCP. It includes checking whether a TCP connection can be successfully established on a specified port and monitoring the data transfer’s reliability and efficiency.

Benefits

• Reliability Assurance: Guarantees that applications dependent on TCP are consistently available and data integrity is maintained.
• Performance Optimization: Helps in identifying bottlenecks and improving the speed and efficiency of data transmission.
• Issue Detection and Resolution: Facilitates early detection of network problems, allowing for timely troubleshooting and minimization of downtime.

UDP Monitoring: An Overview

UDP monitoring is a technique used to ensure that applications which do not require reliable data transmission but need high speed and efficiency are running correctly.

How It Works

UDP monitoring checks the availability of services using the UDP protocol by sending packets to a specified port and waiting for a response. Unlike TCP, it does not establish a connection, making the monitoring process less intrusive and faster.

Benefits

• Speed Verification: Confirms that services are performing at the required speed for optimal user experience.
• Service Availability: Ensures that UDP-based services are accessible to users when needed.
• Efficiency Improvement: Helps in detecting inefficiencies and potential disruptions in real-time services.

TCP Monitoring vs UDP Monitoring

While both TCP and UDP monitoring are vital for network health, their applications and focus areas differ significantly:

• Application Sensitivity: TCP monitoring is essential for applications that cannot tolerate data loss, such as web and email services. UDP monitoring, however, is crucial for applications where speed and efficiency are more critical than absolute reliability, such as live video streaming or online gaming.
• Monitoring Focus: TCP monitoring emphasizes connection reliability and order of data delivery, while UDP monitoring targets service availability and performance metrics for applications sensitive to delays.
• Security Considerations: Both protocols require monitoring for security, but the nature of the threats may differ. TCP monitoring often looks for signs of connection hijacking or data tampering, whereas UDP monitoring might focus more on flood attacks or packet spoofing.

The Role of Firewall Monitoring

Within the intricate web of network security practices lies the critical and engaging process known as firewall monitoring. This method meticulously assesses the operational status and effectiveness of firewall configurations, employing TCP and UDP monitoring checks to ensure that specific ports on devices align perfectly with the intended firewall rules and policies.

For example, by deploying a TCP monitoring check to validate the accessibility of port 443, essential for HTTPS traffic, administrators can swiftly be alerted to the service’s status – UP if the port is securely open, confirming that encrypted web services are operational and secure, or DOWN if the port is unexpectedly closed or unresponsive, indicating a critical issue that could compromise secure web access and data integrity.

Suggest page: What HTTP/HTTPS Monitoring is?

This method allows for precise control and verification of firewall functionality, ensuring that only authorized traffic can access the network, thereby significantly enhancing the security posture against potential intrusions or data breaches.

Conclusion

Monitoring TCP and UDP traffic is essential for maintaining network performance, reliability, and security. While TCP monitoring focuses on ensuring data integrity and smooth flow, UDP monitoring is critical for optimizing real-time application performance. Together with firewall monitoring, these practices provide a comprehensive approach to network management, safeguarding against disruptions and threats while ensuring a seamless user experience. As networks evolve, adopting sophisticated monitoring tools and techniques will remain integral to achieving operational excellence and security resilience.

The post Comprehensive Guide on TCP Monitoring vs. UDP Monitoring appeared first on ClouDNS Blog.

DNS explanation

To understand clearly how DNS filtering operates, we need to explain the purpose of the Domain Name System briefly. 

DNS, which stands for “Domain Name System,” converts the names of websites into IP addresses that browsers can recognize. As a result, whenever you visit a website, your browser requests a particular kind of DNS server. This server returns a corresponding IP address after examining the requested domain name. Then, the page can be loaded from there in a split second, providing you full access.

What is DNS filtering?

DNS filtering, or DNS blocking, is a security technique that prevents access to malicious, untrustworthy, or otherwise undesirable domains or IP addresses. When a user attempts to access a web address, the DNS query is compared to a blocklist of undesirable domains or IP addresses. And if a match is found, the domain is not resolved, and access is denied.

How does it work?

It works in a simple way. All DNS queries are routed through a Recursive DNS server (DNS resolver). DNS resolvers that have been specially configured can also act as filters by refusing to resolve queries for specific domains that are tracked in a blocklist, preventing users from accessing those domains. DNS filtering services can also employ an allowlist rather than a blocklist

Let’s say an employee for the organization receives a phishing email. It falls for the trick of clicking a link that takes them to malisiousexample.com. The company’s DNS resolving service, which uses DNS filtering, receives a query from the employee’s computer before it loads the webpage. The DNS resolver will reject the request if the malicious website is listed on the company’s blocklist. This will stop maliciousexample.com from loading and stop the phishing attack.

DNS filtering can ban websites either by IP address or domain name:

• By IP address: The DNS resolver tries to resolve every domain, but the resolver won’t send the result back if the querying device’s IP address is on the blocklist.
• By domain: For some domains, the DNS resolver does not even attempt to resolve, or look up, the IP addresses.

What does having a secure DNS server mean?

A secure DNS server is a DNS resolver that filters unsafe or restricted webpages as part of a DNS filtering service. Some secure DNS servers also offer enhanced privacy to protect user data, such as Private DNS servers, which delete all DNS query records after some time.

Since DNS was not intended with security in mind from the start, there are additional techniques to make the DNS process safer besides DNS filtering. For example, the DNSSEC ensures that DNS resolvers provide accurate information and are not compromised. In addition, DNS over TLS (DoT) and DNS over HTTPS (DoH) encrypt DNS queries and responses, making it difficult for attackers to track a user’s DNS requests.

Why should you filter DNS?

Due to its adaptability, DNS filtering provides customers with advanced customization options. You can select which content types are allowed and which should be blocked based on the requirements of your organization. In addition, you protect your users from harmful content by implementing DNS-based web blocking. In addition, DNS filtering provides additional benefits, such as: 

• Stops visitors from visiting dangerous or harmful websites.
• Includes simple category-based filtering, blacklisting and whitelisting.
• It prevents visitors from going to phishing websites.
• Stops the download of potentially illegal files.
• Make browsing safe and secure for network users, Wi-Fi users, and visitors.
• Restricts malware downloads for users

What types of DNS attacks can target me if I don’t have DNS filtering?

• DNS cache poisoning (DNS spoofing): The goal of this attack is to taint the recursive servers, specifically the cached replies. If they are successful, any following query will receive a poisoned response.
• DNS hijacking: This attack aims to send DNS messages to a different domain name server with completely bogus information to redirect users to dangerous web pages. Because it is sent to a different location, malware on the target client PC might enable all DNS requests to be routed to the attacker’s controllable DNS server.
• DNS tunneling: It drills into DNS messaging and passes malware using SSH, TCP, or HTTP. DNS tunneling entails encoding communications in DNS queries and responses. This DNS attack leaks sensitive information, in which case the constantly changing domain names make it very challenging to catch.

DNS filtering vs Web filtering

There are two different kinds of content filtering: DNS filtering and web filtering. DNS filtering restricts website access based on DNS queries. On the other hand, web filtering prevents access to specific websites based on their URL. As DNS filtering can prevent access to websites even before they are loaded, it is often more effective than web filtering.

In general, web filters are less precise than DNS filters. This is because DNS queries are frequently more accurate than URLs. For instance, a DNS query for “example.com” will always result in the same IP address. But, depending on your region, the example.com URL can change. Whether you are logged in, or not can also affect how it changes.

Web filtering typically takes longer than DNS filtering. This is because DNS queries often resolve more quickly than URLs. DNS filtering might also obstruct access to websites using secure connections (HTTPS).

Comparison DNS filtering with other security measures

DNS filtering is a vital security layer, but it’s important to understand how it compares with other measures:

• Firewalls: Firewalls control incoming and outgoing network traffic based on predefined security rules. While DNS filter blocks access to harmful domains, firewalls regulate data packets based on source, destination, and types of traffic, offering a different layer of security.
• Antivirus Software: Antivirus programs detect, prevent, and remove malware. DNS filter complements this by preventing access to malicious sites where malware can be downloaded, thus reducing the antivirus software’s load.
• Email Filtering: This specifically targets email threats like phishing and spam. DNS filtering adds an extra layer of security by blocking access to malicious links that might be missed by email filters.
• Endpoint Protection: Endpoint protection focuses on securing endpoints in a network. While this is crucial for detecting and responding to attacks, Domain Name System filtering prevents threats at the network level before they reach endpoints.

Can DNS filtering be bypassed?

While DNS filtering is a powerful way of safeguarding against online threats, it is not infallible. Skilled individuals can bypass DNS filters using various methods such as Virtual Private Networks (VPNs), proxy servers, or by changing the DNS settings on their devices. These methods allow users to avoid the restrictions set by DNS filtering by routing their internet traffic through different servers. To counteract this, it’s important for organizations to employ a comprehensive security strategy that includes regular updates and additional protective measures alongside DNS filtering, DDoS Protection, DNSSEC, Private DNS servers, etc. These approaches ensure a robust defence against evolving cyber threats, maintaining the integrity of network security.

Conclusion

DNS filtering is essential for organizations that want to keep their networks and users safe, whether working in a public Wi-Fi environment or within their corporate network. It provides granular customization options to tailor user access policies, block unwanted content, and enhance privacy. With the constant threat of DNS-based attacks on the rise, implementing a reliable DNS filtering service is the key to ensuring a secure connection for all users.

The post What is DNS filtering? Do you need it? appeared first on ClouDNS Blog.