What is the Traceroute command?

The Traceroute command (Tracert on Windows) is a small network diagnostic software that you have built-in on your device and servers for tracing the route, hop by hop to a target.
Many network administrators use the Traceroute command daily. It is a convenient tool that you can use under different operation systems – Windows (Tracert), macOS, Linux (Traceroute), and even on mobile (Android and iOS).
To access the traceroute, you will need to use the Terminal (Linux and macOS) or the Command Prompt (Windows).
You can use the Traceroute and see the full route that the packets take to their destination (domain or IP address). Apart from that, you will see the hostnames and IPs of the routers on the way and the latency, the time it takes for each device to receive and resend the data.
You can see which gateway is discarding your data, and later you can fix it.

How does it work?

When you run a traceroute, you send an IP packet containing the source and destination addresses and the time to live (TTL) for each hop. TTL in packets decreases with each hop. This is to avoid server looping issues. Furthermore, when the TTL is reached, the packet expires and is discarded. When this occurs, Traceroute returns to the sender ICMP Time Exceeded messages (RFC 792). Because small TTL settings cause packets to expire quickly, traceroute forces all routers in a packet’s path to produce the ICMP messages that identify the router.

To better visualize the traceroute’s working mechanism, you can look at the following chart.

Why use the Traceroute or the Tracert command?

The benefits of using the traceroute command or its alternative for Windows called tracert command are:

• Complete route list. You will see all the routers on the way, with their IP addresses and the time it took. You can better understand the network.
• Route timing. See how much time does it take to finish the query. Is it ok for you? What can you do to speed it up? You can have a starting point for improvements.
• It is built-in. You don’t need to install additional software, and its use is free.
• Check if you can reach a target. See if there is a connection between your device and the hostname or IP address you put in the command.
• See problematic slow router. You can see how much time it took in each hop. So you can see a spot that significantly slows your network. You can fix the problem or add more presence in the area.

When will you need it?

Here are several scenarios where using a traceroute to diagnose a problem you are having can be necessary.

• Sluggish site

Run a traceroute from your computer to your website if you find it is operating slowly. With it, you will check for networking issues between your location and the server.

• Customer timeouts for email

Run a traceroute to assess the quality of the connection to the mail server if you have problems with your mail connection. In addition, you can find your mail server IP by running the following command: “ping smtp.server.com”. It will return the IP address of the Simple Mail Transfer Protocol (SMTP) server that you need for Traceroute purposes.

How to use the Traceroute command?

Use the Traceroute command by writing the command “traceroute + domain.com / IP address” or, in the Terminal on Linux and macOS or “tracert + domain.com / IP address” in the Command Prompt on Windows.

Traceroute (Linux and macOS)

traceroute domian.com or traceroute 12.23.34.45

Tracert (Windows)

tracert domian.com or tracert 12.23.34.45

On macOS, you can also use the Traceroute utility. Press the command button + space. Then write Network Utility. Inside it, navigate to Traceroute. Write the hostname or IP address and press enter. It will show you the result.

*You can change the domain.com with another domain you want to probe, and the same goes for the IP address.

Some differences between the Traceroute command, and the Tracert exist. Check the options below.

Traceroute command vs Tracert command

Apart from the small difference between typing traceroute and the Tracert, the fact that the first works on Linux and macOS, and the second on Windows, the other significant differences are the syntax and the options.

Syntax of the traceroute and Tracert commands

traceroute [options] host_Address [pathlength] (Linux)

traceroute [options] host [packetsize] (macOS)

tracert [-d] [-h maximum_hops] [-j host-list] [-w timeout] [-R] [-S srcaddr] [-4] [-6] target_name (Windows)

Example of Traceroute (Tracert on Windows)

The name of Traceroute on Windows is Tracert. It works very similar to the version on the other operating systems.

And this is how the Traceroute command looks on Linux and macOS:

Traceroute options for Linux

If you are a Linux user (Ubuntu, Linux Mint, Manjaro, Red Hat, Debian, etc.), you can specify your traceroute command with the following options:

rDNS explained in detail

Traceroute options for Windows

You can use the Tracert command with various options to perform more precise tests. The following options work on Windows Vista, Windows 7, Windows 8, and of course, Windows 10.

Traceroute options for macOS

While the Traceroute command on macOS is very similar to its Linux version, there are small differences in their options.

Save Traceroute results for later analysis

Traceroute outputs can be long and detailed, especially when diagnosing complex networks. Saving the results for future analysis helps document network issues, allowing users to track changes, compare routes, or share the data with colleagues or support teams.

To save traceroute results to a file, simply redirect the output into a text file using the following syntax:

For Linux/macOS:

traceroute example.com > traceroute_results.txt

For Windows:

tracert example.com > tracert_results.txt

This command captures the entire output of the traceroute (or tracert) command and saves it in a file called traceroute_results.txt in the current directory. You can then review or share this file at any time, making it easier to troubleshoot ongoing network issues without needing to rerun the command.

The TTL and Traceroute

Each packet that you send contains a TTL (time to live). It is not a time but a limit of hops it can do before getting the result.

Usual limit is 30, but it can be more like 64 for example. This limit stops your data after a certain amount of hops so it won’t go forever. The IP packet will follow until it gets “time exceeded” or “port unreachable” when it gets to the host.

Starting at 30, on the next hop, it will drop to 29 and so on. If it can’t find the domain or IP that you wanted it will display a message where did it fail, so you will know where the problem is.

Distinction between Ping and Traceroute

Both Ping and Traceroute are tools for analyzing networks. However, the Traceroute is a little more advanced. For example, ping will check the connectivity between two hosts but does not reveal the route between them. On the opposite, the Traceroute shows every stop between the source and the final destination. This can be helpful when connectivity is patchy, such as when only 50% of ping attempts between two places are thriving.

So, to sum up, the Traceroute command can be used to identify connectivity issues, while ping is a quick approach to determine whether a host is reachable over a network. Both of these commands are beneficial to be aware of because knowing how they operate and what their output denotes can be very valuable when analyzing network connectivity issues.

Traceroute’s Restrictions

• It establishes the route at the interface level rather than at the router level.
• The Traceroute may not respond after crossing the maximum number of hops if there are firewalls between the source and destination routers that prevent the probe packets from being sent. Furthermore, despite the hops IP address, the router will display * (asterisk) if no response is received. Therefore, using a traceroute under these circumstances is not suggested.
• Based on the IP headers, load balancing routers can route the traffic via a number of different paths. Therefore, if we execute a traceroute in this case, it will give us an incorrect path between the origin and the goal. Accordingly, it is not advisable to employ traceroutes in this circumstance either.

Are there alternatives to the traceroute command?

Yes, there are various alternatives to the traceroute commands like MTR command, Dig command, Open Visual Traceroute, Nmap.

MTR command (Linux and macOS)

mtr domain.com

The MTR command is an improved traceroute command that can give more statistics and data for lost packets (percentage).

Dig command (Linux and macOS)

dig +trace domain.com

If you already use the Dig command, you can use it for tracing the route too.

Open Visual Traceroute (Linux, macOS, and Windows)

This one is for people who want a visual interface. It is heavier, but it can show you, in a graphical way, the route of the queries and also get Gantt graphs.

Nmap (Linux, macOS, Windows, BSD, and more)

nmap –traceroute domain.com

The results are very similar to the traceroute command.

Conclusion

By using the newly collected data, you can see if there is any problem on the route (not responsive server or very slow one) and later focus your attention to fix it. If you want to see few more tools you can check one of our previous article Тools – DNS trace, Ping, Traceroute, Nslookup, Reverse lookup.

The post Traceroute command and its options appeared first on ClouDNS Blog.

What is Round-Trip Time (RTT)?

Round-Trip Time is a network performance metric representing the time it takes for a data packet to travel from the source to the destination and back to the source. It is often measured in milliseconds (ms) and is a crucial parameter for determining the quality and efficiency of network connections.

To understand the concept of RTT, imagine sending a letter to a friend through the postal service. The time it takes for the letter to reach your friend and for your friend to send a reply back to you forms the Round-Trip Time for your communication. Similarly, in computer networks, data packets are like those letters, and RTT represents the time it takes for them to complete a round trip.

How Does it Work?

The concept of RTT can be best understood by considering the journey of data packets across a network. When you request information from a web server, for example, your device sends out a data packet holding your request. This packet travels through various network devices in between, such as routers and switches, before reaching the destination server. Once the server processes your request and prepares a response, it sends a data packet back to your device.

Round-Trip Time is determined by the time it takes for this data packet to travel from your device to the server (the outbound trip) and then back from the server to your device (the inbound trip). The total RTT is the sum of these two one-way trips.

Let’s break down the journey of a data packet into several steps so you can better understand the RTT:

1. Sending the Packet: You initiate an action on your device that requires data transmission. For example, this could be sending an email, loading a webpage, or making a video call.
2. Packet Travel: The data packet travels from your device to a server, typically passing through multiple network nodes and routers along the way. These middle points play a significant role in determining the RTT.
3. Processing Time: The server receives the packet, processes the request, and sends a response back to your device. This processing time at both ends also contributes to the Round-Trip Time.
4. Return Journey: The response packet makes its way back to your device through the same network infrastructure, facing potential delays on the route.
5. Calculation: It is calculated by adding up the time taken for the packet to travel from your device to the server (the outbound trip) and the time it takes for the response to return (the inbound trip).

Why does it matter?

At first look, Round-Trip Time (RTT) might seem like technical terminology, but its importance extends to various aspects of our digital lives. It matters for many reasons, which include the following:

• User Experience

For everyday internet users, RTT influences the sensed speed and responsiveness of online activities. Low Round-Trip Time values lead to a seamless experience, while high RTT can result in frustrating delays and lag during tasks like video streaming, online gaming, or live chats.

• Network Efficiency

Network administrators and service providers closely monitor RTT to assess network performance and troubleshoot issues. By identifying bottlenecks and areas with high RTT, they can optimize their infrastructure for better efficiency.

• Real-Time Applications

Applications that rely on real-time data transmission, such as VoIP calls, video conferencing, and online gaming, are highly sensitive to RTT. Low RTT is crucial for smooth, interruption-free interactions.

• Security

In cybersecurity, Round-Trip Time plays a role in detecting network anomalies and potential threats. Unusually high RTT values can be a sign of malicious activity or network congestion.

Tools for Measuring RTT

Measuring Round-Trip Time is essential for understanding network performance. Two of the most commonly used tools are Ping and Traceroute. Here’s how to use them:

• Ping command

The Ping command is a fundamental tool available on most operating systems. It measures RTT by sending Internet Control Message Protocol (ICMP) echo requests to a specified IP address. It calculates the time it takes for a packet to travel to the target and back, providing the RTT in milliseconds. This tool is valuable for basic network diagnostics, helping you identify if a host is reachable and how long it takes to communicate with it. You can easily use it by following these steps:

1. Open Command Prompt (Windows) or Terminal (macOS/Linux).
2. Type “ping” and the target domain or IP address. Here is an example: ping domain.com
3. Press Enter.

The output will display the RTT in milliseconds for each packet sent.

• Traceroute/Tracert

Traceroute (or Tracert in Windows) is a diagnostic tool that goes beyond just measuring RTT. It traces the entire path a packet takes to reach its destination, displaying each hop along the route and the RTT to each router. That way, it helps identify where delays or packet loss occur in the network, making it a crucial tool for finding issues in complex networks. To utilize it, follow the steps below:

1. Open Command Prompt (Windows) or Terminal (macOS/Linux).
2. Type “tracert” (Windows) or “traceroute” (macOS/Linux) followed by the target domain or IP address. Here is an illustration: traceroute domain.com
3. Press Enter.

The output will show the RTT for each hop along the route to the destination.

Factors Affecting Round-Trip Time (RTT)

Several factors can influence the metric, both positively and negatively. Therefore, understanding these factors is crucial, and it could be very beneficial for optimizing network performance:

• Distance: The physical distance between the source and destination plays a significant role. Longer distances result in higher RTT due to the time it takes for data to travel the network.
• Network Congestion: When a network experiences high volumes of traffic or congestion, data packets may be delayed as they wait for their turn to be processed. As a result, it can lead to packet delays and increased RTT.
• Routing: The path a packet takes through the network can significantly affect RTT. Efficient routing algorithms can reduce the time, while not-so-optimal routing choices can increase it.
• Packet Loss: Packet loss during transmission can occur due to various reasons, such as network errors or congestion. When lost, packets need to be retransmitted, which can seriously affect the Round-Trip Time.
• Transmission Medium: It is a critical factor influencing RTT, and its characteristics can vary widely based on the specific medium being used. Fiber optic cables generally offer low RTT due to the speed of light in the medium and low signal loss. In contrast, wireless mediums can introduce variable delays depending on environmental factors and network conditions.

How to improve it?

Improving Round-Trip Time (RTT) is a critical goal for network administrators and service providers looking to enhance user experiences and optimize their digital operations. While some factors affecting it are beyond our control, there are strategies and practices to optimize Round-Trip Time for a smoother online experience:

• Optimize Routing: Network administrators can optimize routing to reduce the number of hops data packets take to reach their destination. This can be achieved through efficient routing protocols and load balancing.
• Optimize Network Infrastructure: For businesses, investing in efficient network infrastructure, including high-performance routers and switches, can reduce internal network delays and improve RTT.
• Upgrade Hardware and Software: Keeping networking equipment and software up-to-date ensures that you benefit from the latest technologies and optimizations that can decrease RTT.
• Implement Caching: Caching frequently requested data closer to end-users can dramatically reduce the need for data to travel long distances. The result really helps with lowering RTT.
• Monitor and Troubleshoot: Regularly monitor your network for signs of congestion or packet loss. If issues arise, take steps to troubleshoot and resolve them promptly.

Discover ClouDNS Monitoring service!

RTT vs Latency

RTT and latency are related but not identical metrics in networking. Latency is the time it takes for a packet to travel from the source to the destination, often referred to as a one-way delay. RTT, on the other hand, measures the total time it takes for a packet to go to the destination and for a response to come back to the source.

It is important to mention that RTT is not always exactly twice the latency. Factors such as network congestion, processing delays at routers, and asymmetrical routing can cause RTT to differ from simply doubling the latency. For example, if the route from source to destination is more congested or longer in one direction, the round-trip time might be significantly higher than twice the latency.

Conclusion

Round-Trip Time (RTT) is the silent force that shapes our online experiences. From the seamless loading of web pages to the quality of our video calls, RTT plays a pivotal role in ensuring that digital interactions happen at the speed of thought. As we continue to rely on the Internet for work, entertainment, and communication, understanding and optimizing this metric will be crucial for both end-users and network administrators. By reducing it through strategies, we can have a faster, more responsive digital world where our online activities are limited only by our imagination, not by lag.

The post Round-Trip Time (RTT): What It Is and Why It Matters 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.

However, like every other IT problem, DNS issues can be resolved. You just have to know the right tools and commands. In this blog post, we’ll delve into some of these essential DNS troubleshooting tools and commands that every network administrator ought to arm themselves with.

Common DNS Issues 

Before we dive into the tools and commands, let’s understand the most common DNS issues that most administrators often encounter:

1. DNS Downtime: This occurs when DNS servers that translate domain names are temporarily unavailable.
2. Incorrect DNS Configuration: This involves errors in the setup of DNS settings which may lead to problems accessing certain websites or the internet.
3. DNS Cache Poisoning: Also known as DNS Spoofing, it refers to fraudulent entries in the DNS cache, causing traffic to be directed to the wrong place.
4. DNS Propagation Delays: This happens when you make changes to your DNS records and they are not immediately effective due to the time taken to update network servers around the globe.

Now that we have a basic understanding of common DNS issues, let’s explore the essential DNS troubleshooting commands that can help you diagnose and resolve these problems.

DNS Troubleshooting Tools

There are plenty of tools that you can use. The tools can be specific for Linux, Windows, or Mac OS, or they can be browser-based. Most of the tools that we will show you overlaps in functionality, and it will be your decision which one you would use in the future.

Check if the problem is not just in your device

Before you start with the DNS troubleshooting, check if the problem is only local. If you are trying to access your website, but you are getting this message “DNS_PROBE_FINISHED_NXDOMAIN” the problem might be in your device. We recently wrote a way to fix it. Go and read the article. 

Dig command

The ‘dig’ command, which stands for ‘Domain Information Groper,’ is a handy command-line tool used in the DNS name resolution process. It sends a DNS query to a specified DNS server and gets a response. It’s a useful tool for finding DNS-related issues. 

With this command you can see all the DNS records. You can use it on Linux and Mac OS, but you can search for a port for Windows too. A typical dig command will show you an Authority Section. You can see if the DNS is pointing correctly.

Use it with +trace in dig +trace combination “dig +trace YOURDOMAIN” to see the whole route of your query. This way you can locate the exact problem.

ClouDNS Free DNS tool

ClouDNS brings to you a valuable Free DNS tool that has transformative capabilities to enhance your DNS troubleshooting tactics. With this tool, you can inspect the DNS records for a specific host and assess the speed of DNS queries. Aside from these, you can also create a comprehensive audit, a feature that helps in in-depth analysis and identification of problematic areas.

Designed to facilitate the work of their customers, the ClouDNS Free DNS tool is user-friendly and accessible, making DNS troubleshooting a breeze even for beginners in the field. All you need to do is enter your domain and host into the tool, select the tool type as “DNS Records”, and choose ‘Google’ as your DNS resolver, then hit ‘CHECK’. 

What’s more, this powerhouse tool is free of cost, making it a stellar choice for efficient network management. The value it provides, particularly in terms of insight into DNS records and query speed, can go a long way in troubleshooting DNS-related problems swiftly and effectively.

Traceroute

The ‘traceroute’ command enables you to track the pathway that a packet takes from the host to the destination server. As the name suggests, this will be ideal for checking the entire route of a DNS query. You can use it on Windows as Tracert, Linux and Mac OS as traceroute. You can try it with a domain or IP address, and you will see a result with all the hops and response time.

NSLookup

‘NSLookup‘ stands for ‘Name Server Lookup’. This command-line tool is used for obtaining information about DNS settings. It allows users to enter a host name and find out the corresponding IP address, or vice versa.

This command lets you check any type of DNS record. You can use it to see all the available DNS records, or you can look for a specific type like – A, AAAA, SOA, MX, PTR, NS, etc. You can use it to troubleshoot a domain using a particular port too. 

Host command

‘Host’ command is very similar to the NSLookup but available only on Linux. You have to write the commands in the Terminal, and you can see the different types of DNS records.

One thing that you can troubleshoot if you have problems with your emails are the TXT records. You can see if there is a SPF record. It is a TXT record that prevents spoofing and stops your outgoing emails from going directly into the spam folder.

Generate SPF record for free!

Conclusion

There are plenty of useful tools that you can use for DNS troubleshooting. Try all of these and find the right one for you and your problem. Many overlaps in functionality, but have some small differences that can help you in a specific case.

As you saw, there are utilities for every operating system so that you can find the problem easily. After you see where the problem is, it is easy to fix it.  

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