A Brief History of Hubs and Switches in Networking

In the early 1980s, hubs were introduced as basic devices for connecting multiple computers in a local area network (LAN). Operating at the physical layer (Layer 1) of the OSI model, hubs broadcasted data to all connected devices simultaneously, which was sufficient for small, low-traffic networks of the time. However, this method led to data collisions and inefficient use of bandwidth as networks grew.

By the mid-1990s, switches began to emerge as a more advanced alternative. Operating at the data link layer (Layer 2), switches could direct data packets specifically to the intended recipient device using MAC addresses. This innovation reduced collisions and allowed for more efficient use of network resources, leading to their increased adoption.

Now, let’s dive into the main differences between hubs and switches, and explore which one is better suited for your specific networking needs.

Hub

A hub, as the name suggests, is a connection point for various computers. It creates a network based on Ethernet. There are variations based on USB and Firewire too.

This device does not manage the traffic intelligently. It broadcast the data to all of the connected computers.  Because of the way it works, more bandwidth is used and occasionally packet collisions occur.

Advantages of using a Hub

Low Cost

Budget-Friendly: Hubs are generally more budget-friendly than switches. This can be advantageous for temporary setups or when networking needs are minimal, making them an economical choice for small or short-term projects.
Reduced Total Cost of Ownership: Lower initial cost means that the total cost of ownership (TCO) is generally less for hubs, assuming the lack of features is not a hindrance to the network’s purpose.

Ease of Setup

Plug-and-Play: Hubs usually require minimal setup. In most cases, you simply plug your devices into the hub, and you’re good to go.
No Configuration Needed: Unlike switches, hubs do not require any configuration, making them easier to deploy for those who may not be technologically savvy.

Disadvantages of using a Hub

No Traffic Management

Bandwidth Sharing: All devices connected to the hub have to share the bandwidth, which can be problematic when you have multiple devices transmitting data simultaneously. This is particularly limiting for applications that require high data throughput.
Collisions: The lack of traffic management means that data collisions are more likely to occur, making hubs less reliable for transmitting data effectively.

Limited Security

Data Vulnerability: Because all data packets are broadcasted to every port, it’s easier for malicious actors to sniff data. This is particularly problematic if sensitive information is being transmitted.
No Access Control: Hubs do not have features to restrict access to connected devices. This makes network management and security more challenging.

Reduced Performance

Limited Scalability: Due to inefficiency in handling network traffic, hubs are not suitable for networks that may need to scale. As more devices are added, performance degrades significantly.
Latency: Because each packet is sent to all ports, it takes more time for the correct packet to reach its destination, leading to latency issues.

Switch

The switch is a smart network device. In contrast to the hub, it reviews the packets of data and directs them just to the right one. It does that by remembering the MAC addresses of the connected gadgets. The switch can support different common network types like 802.11, Ethernet, Fibre and more. It is newer in comparison with the hub, and it is more common in the modern offices.

Advantages of using a Switch

Efficient Traffic Management

Dedicated Bandwidth: Unlike hubs, switches provide dedicated bandwidth to each connected device, allowing for smoother data transmission.
Smart Data Packet Handling: Switches can understand the data packets they receive and send them only to intended devices, reducing the likelihood of data collision.

Enhanced Security

Secure Data Transmission: By sending packets only to intended recipients, switches make it more difficult for unauthorized users to intercept data.
Access Control: Managed switches allow network administrators to set up Access Control Lists (ACLs), providing an extra layer of security.

Better Performance

High Throughput: With better traffic management, switches can handle a larger amount of data traffic without sacrificing speed.
Scalability: Switches are more suited for growing networks, providing stable performance even as more devices are added.

Disadvantages of using a Switch

Cost

Higher Initial Cost: The upfront cost of a switch is generally higher than that of a hub.
Total Cost of Ownership: The advanced features may require ongoing maintenance, increasing the total cost over time.

Complexity

Configuration Required: Switches usually need to be configured, which might require specialized knowledge or expertise.
Compatibility Issues: Advanced features like VLANs or Quality of Service (QoS) settings can sometimes cause compatibility issues with older hardware or software.

Hub vs. switch

Now, let’s get more concrete. With this table of comparison, you will know why people prefer the switch.

What should you use?

Small Home Networks:

If you have a small home network with limited data transfer requirements, a hub could suffice. However, modern-day routers often come with built-in switch ports, providing even small home networks with the advantages of switches without requiring a separate device.

Business Networks:

For business settings, a switch is almost always the better choice. The increased performance and security features are typically necessary for a business network to run efficiently.

Specialized Needs:

If you need to monitor all the data traffic for purposes like data sniffing or analysis, a hub could be beneficial because it sends packets to all ports. But such tasks are better suited for managed switches with port-mirroring features.

Suggested page: Monitoring service: What is it and do I need it?

Conclusion

And now, the final answer of  “Hub vs. switch”.

Depends a lot on your budget. If you are searching for the cheapest option out there, or maybe you have an old big hub lying somewhere you could still use it. It can be a solution for a small network of computers that are not connected to the Internet.

In any other case, chose a switch. It is smarter, more secure and it can manage a larger group of connected devices.

The post Hub vs. switch. What should you use for your network? appeared first on ClouDNS Blog.

Router

A router is one of the network devices that handles network traffic. It does it by forwarding data packets between different computer networks. When the router receives the data packets, it will check it, and it will compare it with its routing table. Then it will decide to send it to the next network toward the destination of the packets or not. Most of you are probably familiar with the routers. You probably have one at home, which manages packets from the home computer to the internet.

Functionalities of routers 

• IP address management: Routers assign IP addresses to devices within a network and provide network address translation (NAT) functionality to map multiple private IP addresses to a single public IP address.
• Traffic management: Routers implement Quality of Service (QoS) mechanisms to prioritize and manage network traffic based on predefined rules.
• Network segmentation: Routers allow for the creation of separate network segments, known as subnets, to enhance security and optimize network performance.

Firewall

Firewall, as the name suggests, is a barrier. Its purpose is to protect the devices behind it by filtering the data from coming to them and going from them and protecting from harmful communications like spam or viruses. It can be hardware, with router capability or just software, like the one Windows has.

Key features of firewalls

• Packet filtering: Firewalls examine packets based on predefined rules, such as source/destination IP addresses, ports, and protocols, to determine whether they should be allowed or blocked.
• Stateful inspection: Firewalls maintain state information about established connections, allowing them to make intelligent decisions regarding packet filtering and preventing unauthorized access.
• Application-level filtering: Some firewalls can perform deep packet inspection to analyze the content of packets at the application layer (Layer 7), enabling them to detect and block specific application-layer threats.

Importance of Firewall Monitoring

Firewall monitoring is a critical aspect of network security management. It involves continuous monitoring, analysis, and maintenance of firewall rules and logs to ensure optimal firewall performance and detect potential security incidents. Effective Dynamic Host Configuration Protocol provides the following 4 benefits:

1. Threat detection and prevention: By monitoring firewall logs and analyzing network traffic patterns, administrators can identify suspicious activities, such as unauthorized access attempts, malware infections, or data exfiltration, and take proactive measures to mitigate them.
2. Policy compliance: Firewall monitoring helps ensure that security policies and rules are consistently enforced, reducing the risk of policy violations and non-compliance with industry regulations.
3. Performance optimization: Regular monitoring enables administrators to identify and resolve performance bottlenecks, fine-tune firewall configurations, and optimize network traffic flow, thus enhancing overall network performance.
4. Incident response: In the event of a security incident, firewall logs provide crucial information for forensic analysis and incident response. Monitoring allows for the timely detection and response to security breaches, minimizing potential damage.

Router vs firewall

To easily understand the router vs firewall topic, see this table:

Hardware firewall vs software firewall

Now to a bit of a different subject, hardware firewall vs software firewall. Both protect you from malicious traffic, but they have some differences.

The hardware firewall can be a stand-alone device or a part of a router. Such a router is a simple and effective protection solution for your network. It reviews the headers of the data packets and decides if it can be trusted. If it thinks the packet is safe, it will forward it, if no, it will drop it.

A software firewall is a program that you can install on your computer. It can be a part of an antivirus suite or separate. It will protect from uncontrolled access to your computer. Depending on the software, it can keep you safe from Trojans and worms too. The difference with the hardware one, this one will protect just the device that has the firewall installed. If you need a firewall on all of your devices, you would need to install it on all of them. Another disadvantage of it is that it will run in the background, which will take some system resources and may lead to slowdowns.

How do DHCP, routers, and firewalls work together?

DHCP, which stands for Dynamic Host Configuration Protocol, is responsible for assigning IP addresses to devices within a network. It acts as a mediator between routers and firewalls, ensuring that devices can communicate with each other and stay secure.

Routers are like traffic directors. They help direct data packets between different networks, ensuring they reach their intended destinations. Some routers also have built-in DHCP server functionality, allowing them to assign IP addresses to devices in the network.

Firewalls, on the other hand, are like security guards. They monitor and control the flow of network traffic to protect against unauthorized access and potential threats. While firewalls primarily focus on security, they can interact with DHCP in a couple of ways.

Firstly, firewalls can act as DHCP relays. If devices and DHCP servers are on different network segments, the firewall helps relay the DHCP messages between them, ensuring that devices can still get their assigned IP addresses.

Secondly, firewalls can inspect DHCP traffic and apply rules to allow or block it. This filtering capability helps prevent unauthorized DHCP servers or DHCP attacks from compromising the network’s security.

Lastly, firewalls can use DHCP lease information to enforce security policies. By looking at the DHCP lease table, they can identify devices based on their assigned IP addresses and apply specific security rules or identify potential unauthorized devices on the network.

In simpler terms, DHCP ensures devices have IP addresses to communicate, routers direct the traffic, and firewalls protect the network by working alongside DHCP to manage IP addresses and filter network traffic.

Switches vs routers vs firewalls: How do they fit together?

In a typical network setup, devices such as computers and printers connect to a switch. The switch facilitates internal communication within the local network by forwarding data packets based on MAC addresses.

The switch then connects to a router. The router manages traffic between different networks by using IP addresses to route data packets. It ensures that data from your local network reaches its destination on other networks, such as the internet.

Finally, the router connects to a firewall. The firewall acts as a barrier, inspecting and filtering traffic to protect your network from unauthorized access and cyber threats. By examining data packets based on security rules, the firewall ensures that only safe and authorized traffic enters or leaves the network.

Example Setup:

Devices -> Switch -> Router -> Firewall -> Internet

This configuration ensures that devices can communicate within the local network, that traffic is efficiently managed and routed to appropriate destinations, and that the network is protected from external threats. This collaborative setup of switches, routers, and firewalls provides a robust, efficient, and secure network infrastructure.

Conclusion

Routers and firewalls play vital roles in securing networks and protecting sensitive information. While routers focus on efficiently forwarding data packets between networks, firewalls provide an additional layer of security by monitoring and controlling network traffic based on predefined rules. Both are essential components of a robust network security architecture.

The post Router vs firewall, can you guess which is better? appeared first on ClouDNS Blog.

Before the Internet and the DNS

Let’s get back to the time when the Internet didn’t exist. Yes, there was such a time, even if you don’t remember it. The Cold War was on, the USA was investing a lot in defense and technology. In 1958, under the president Eisenhower, ARPA (Advanced Research Projects Agency) started. It was a big step for the American science and a response to the Soviet achievements (Sputnik 1, 1957).

In the 60s ARPA was getting stronger and bigger. It got more hardware, including the Q-32 computer. The idea of computer networking was starting to catch on.
MIT (Massachusetts Institute of Technology) was working close with ARPA, and there was some serious progress about creating a network. The idea of packet switching was presented, and there was a project to connect the Q-32 to the TX-2 computer (MIT’s computer) under the management of Larry Roberts. Later in 1966, the same guy published a paper on ARPANET – a packet switching network that uses TCP/IP protocol. It was like the Internet, but not scalable. It took some more years before it gets a reality.

During the 70s there was a fast growth in the numbers of computers in the world. There were different networks appearing and even some international projects too. There was a lot of development, and many different protocols and programs were created. The first commercial e-mail programs came in 1976.

A year later, the first 3-network system was introduced. Packet radio, ARPANET, and SATNET were working together!

The technological progress was going so fast, but people were starting to have a severe problem with bookkeeping. There was no one united network, but rather a system of networks. The need for a global solution was strong and here comes the DNS!

The DNS history start

Initially, the process of assigning addresses was manual. Computers and their associated hostnames and addresses were added to the HOSTS.TXT file by contacting the SRI Network Information Center (NIC) via telephone during business hours. As the network grew, Feinler introduced the WHOIS directory on a NIC server, allowing retrieval of information about resources and contacts.

The task of simplifying the networking was given to Paul Mockapetris. He and his team had the mission to create a friendlier for use network, where people wouldn’t need to remember the IP address of every computer. Before, there was a centralized HOSTS.TXT text that was mapping the current sites. But, thanks to the growing number of sites, the file was getting bigger too, and there was a strong need for a decentralized model.

Paul Mockapetris: “It was created to let people use names for anything. But we had to figure out how to organize the distribution of domain names and how to ensure the system could accommodate diversity without unnecessary restriction.”

The DNS was created in 1983 and became one of the original Internet Standards in 1986 (After the creation of the Internet Engineering Task Force IETF). In 1984, UC Berkeley students developed the first Unix name server implementation known as BIND (Berkeley Internet Name Domain). Over the years, various developers and organizations, including the Internet Systems Consortium (ISC), contributed to the maintenance and development of BIND. In November 1987, RFC 1034 and RFC 1035 replaced the original DNS specifications from 1983. They describe the whole protocol functionality and include data types that it can carry.

RFC 1034 and RFC 1035: Defining the DNS Protocol

The RFC 1034 and RFC 1035 hold immense significance in the world of DNS as they define the very foundations of the DNS protocol. RFC 1034, published in 1983 and titled “Domain Names – Concepts and Facilities,” provides a comprehensive overview of the DNS architecture and its key components. It lays out the fundamental concepts and operations of DNS, introducing terms such as domain names, name servers, and resource records. By establishing a standardized framework, RFC 1034 enables interoperability and consistency across the DNS infrastructure. It serves as a vital reference for implementing DNS systems and understanding the core principles that govern name resolution on the Internet.

Complementing RFC 1034, RFC 1035, published in 1986 and titled “Domain Names – Implementation and Specification,” delves deeper into the technical aspects of the DNS protocol. It provides detailed specifications for message formats, data types, and the structure of DNS packets. RFC 1035 outlines the specific operations and algorithms used in resolving domain names to IP addresses and vice versa. It also introduces caching mechanisms that improve DNS performance by reducing the need for repeated queries. These two documents together form the backbone of the DNS protocol, ensuring consistent behavior and facilitating seamless communication between DNS resolvers, name servers, and clients.

The significance of RFC 1034 and RFC 1035 extends beyond their technical specifications. They represent a collaborative effort of experts and enthusiasts who shaped the early Internet and established the groundwork for modern-day networking. These documents continue to serve as a vital resource for developers, network administrators, and researchers, ensuring the integrity and interoperability of the DNS ecosystem. 

DNS Nowadays

The DNS has seen various upgrades during its life. The first major one was the introduction of the NOTIFY mechanisms and Incremental Zone Transfer IXFR. Now the servers were able to update dynamically. With the NOTIFY, the master server can “say” to the slave servers that it has an update that it must share. Before, the slaves needed to check periodically. And the second IXFR, now those slaves servers, didn’t need to update the whole zone file, they could update just the changes.

Today, DNS operates on a hierarchical and decentralized structure. The DNS system consists of multiple interconnected servers that collectively store and manage DNS records. These servers are categorized into different types, including root servers, top-level domain (TLD) servers, and authoritative name servers. When a user enters a domain name in their web browser, their device initiates a DNS lookup process to find the corresponding IP address.

DNS has evolved over the years to meet the growing Internet demands. It has incorporated various enhancements, including security features like DNSSEC (Domain Name System Security Extensions), to protect against DNS poison attacks. Additionally, DNS-based technologies like DNS Load Balancing and Content Delivery Networks have been developed to optimize website performance and ensure high availability.

The Future of DNS: Trends and Innovations to Watch Out For

As technology advances, prioritizing website speed and security stands out as the cornerstones of optimal DNS performance. As a result, companies are investing heavily in newer technologies to enhance user experience and ensure reliability.

The movements to switch to DNS over HTTPS are gaining momentum as it provides added protections to mitigate the threat of cybercrimes and preserves user privacy. Another emerging trend is DNS over TLS as companies seek to build trust and improve security. By adding an extra layer of protection, DoH and DoT make it more difficult for malicious actors to intercept or manipulate DNS queries, ensuring a safer and more reliable browsing experience for users. Additionally, DNS-based service discovery is also one to look out for, allowing IT teams to use DNS or DNS-related protocols to perform automated mapping or workloads.

Ultimately, the future of DNS depends on the ability of organizations to adopt these emerging trends and invest in the right DNS technologies to maximize user experience and data security.

Conclusion

The Domain Name System (DNS) has come a long way since its humble beginnings as a centralized text file, HOSTS.TXT, mapping out the ever-increasing number of sites on the web. Thanks to the advancements of Larry Roberts and Paul Mockapetris, the DNS was created to simplify the networking experience. Since then, we’ve seen various upgrades, such as the NOTIFY mechanisms and DNSSEC, to improve both performance and security. As the world of technology continues to evolve, the future of the DNS should remain at the forefront of our minds.

The post DNS history. When and why was DNS created? appeared first on ClouDNS Blog.

What is DNS_PROBE_FINISHED_NXDOMAIN?

It is a DNS-related error that shows that the domain that you are trying to reach does not exist (NXDOMAIN means non-existing domain). The DNS can’t find the corresponding IP address to the domain you just entered.
Most of the times this is a DNS configuration problem, and the problem is in your device, not in the domain itself.

Ok, we said Chrome, but does this happen when you are using other browsers?

We mention Google Chrome, where you get “This site can’t be reached,” but you can get a similar message in any other browser. Mozilla’s Firefox will show you “Hmm. We’re having trouble finding that site”, Microsoft Edge “Hmmm… can’t reach this page”, and almost identical messages on the rest of the browsers.

Ok, so what to do when we see the DNS_PROBE_FINISHED_NXDOMAIN?

There are several ways that you can fix your problem. Let’s explore the possibilities:

1.    Flush the DNS cache

If it is bad-configured DNS, the easiest is to start from zero. Flush the current DNS cache and renew the IP address.

For Windows users, follow these steps:
Open the Command Prompt as an administrator. Click the start menu icon and write “Command Prompt,” then run as administrator. Then type “ipconfig /release” and press Enter on your keyboard. Now you can see your current IP address. After that, write “ipconfig /flushdns” and press Enter. You flushed the cache, “Successfully flushed the DNS Resolver Cache.” Next thing to type in “ipconfig /renew”. And now your IP address has been renewed.

For Mac OS users:
Go to “System Preferences…”, then “Network” and later “Advanced.” When you are there, go to TCP/IP and click the “Renew DHCP.”
You can also delete the DNS cache. First, open the “Utilities” and then the “Terminal.” The command you need to write is “dscacheutil –flushcache” and press Enter. It is ready. There is no confirmation message here.

For Linux (Linux Mint, Ubuntu):
If you are using Linux Mint or Ubuntu, by default, the DNS cache is disabled. You can check if it is enabled with the following command “ps ax | grep dnsmasq”. In the message that you’ll get check if “cache-size=0”, then it is disabled. If it is enabled, write the following command “udo /etc/init.d/dns-clean restart”. Then type “sudo /etc/init.d/networking force-reload”. Done!

2.    Reinitiate the DNS Client Server.

For Windows users, we will use the “Run” to open “services.msc.” Now you will see all the services that run on your computer. Go to DNS Client, stop it and start it again.

3.    Change the DNS servers

Your internet provider automatically set your IP address, using their DNS servers. But you have the chance to change to another DNS server like Google’s public DNS.

Windows:
Go first to “Control Panel,” then “Network and Internet” and later “Network and Sharing Center.” There click the “Change adapter settings” and select the network that you are using. Go to properties, search for the “Internet Protocol Version 4” and click on the properties. Set the following DNS servers 8.8.8.8 and 8.8.4.4

Mac OS:
“System Preferences,” Network,” and then “Advanced.” Click on DNS and add the same 8.8.8.8 and 8.8.4.4.

Linux (Linux Mint, Ubuntu):
Open “System Settings,” “Network.” Then select the network that you are using and choose “Settings.” Go to the “IPv4 Settings,” and there you will see “Additional DNS servers.” add “8.8.8.8, 8.8.4.4”.

4.    Chrome Flags Reset.

Maybe the problem comes from your Chrome browser. Go to your Chrome browser and type “chrome://settings/clearBrowserData” in the address bar. Delete the “Cached images and files,” “Cookie and other site and plugin data” and “Browsing history” from “the beginning of time.”
After that type “chrome://flags/” and a menu will open. Click on the “Reset all to default.” Now restart the browser, and you are ready.

Conclusion

Next time when you see the DNS_PROBE_FINISHED_NXDOMAIN don’t panic. There are easy solutions to this problem. Just try one of those, and you will be ready is a few minutes.
If the site that shows the error is yours, and after trying nothing is happening, go and check if the domain is correctly redirected. If no, do fix it.

Don’t stop following our blog, which is full of exciting and useful articles!

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