Linux commands for network configuration and troubleshooting are covered in this article. The most frequently used commands are covered, as well as some less common but useful commands. This is by no means an exhaustive list, but it should be enough to get you started.
1. ifconfig
Configuring IP addresses on network interfaces is a common task that is performed using the ifconfig command. This command can be used to configure IP addresses, gateways, subnet masks, and other network parameters on Linux machines.
The ifconfig command can be used to display the current configuration of a network interface, or to change the configuration. To view the current configuration of a network interface, use the ifconfig command followed by the name of the interface. For example, to view the configuration of the eth0 interface, use the following command:
ifconfig eth0
This will display the current IP address, gateway, subnet mask, and other information about the eth0 interface.
To change the configuration of a network interface, use the ifconfig command followed by the name of the interface and the new configuration parameters. For example, to change the IP address of the eth0 interface to 192.168.1.100, use the following command:
ifconfig eth0 192.168.1.100
This will change the IP address of the eth0 interface to 192.168.1.100. Remember to use the correct values for your network when changing the configuration of a network interface.
2. route
A route is a specific way that a person or vehicle can travel between two places.
There are many different types of routes, but the most common are road routes, which are designed for cars and other motorized vehicles; and walking routes, which are designed for pedestrians.
Routes can be short or long, and they can be direct or indirect. The best route is the one that gets you where you want to go in the shortest amount of time.
When you’re planning a trip, it’s important to consider the different types of routes that are available to you. The best way to find the perfect route is to use a mapping tool like Google Maps.
3. netstat
Netstat is a command-line network utility that can be used to view network connections and statistics. The netstat command can be used to view all active network connections and their status, as well as view statistics about network traffic. The netstat command is available on all major operating systems, including Windows, Linux, and macOS.
4. traceroute
A traceroute is a network diagnostic tool used to track the path of a packet across an IP network. The traceroute command uses the IP protocol “time to live” field and attempts to elicit an ICMP TIME_EXCEEDED response from each gateway along the path to the host.
The traceroute command is available on most Unix-like operating systems. Windows users can use the tracert command.
The output of a traceroute includes the round-trip time (RTT) to each gateway along the path and the IP address of each gateway. By analyzing the RTT to each gateway, a network administrator can determine which gateway is causing a problem.
The traceroute command is often used by network administrators to troubleshoot network problems. It can also be used by hackers to map out a network for attack.
5. dig
The word “dig” has many meanings in English. It can be used as a verb, meaning to excavate or turn over earth with a shovel or other tool, or as a noun, meaning an excavation or hole in the ground.
When used as a verb, “dig” is often followed by a noun or pronoun to indicate what is being dug. For example, you might say “I’m going to dig a hole in the garden” or “I need to dig my car out of the snow.”
When used as a noun, “dig” can refer to either a physical excavation or hole, or to something that is seen as being deep or difficult to understand. For example, you might say “That hole looks like it’s pretty deep – be careful you don’t hurt yourself” or “This book is really deep – I’m having trouble understanding it.”
6. host
When you visit a website, your computer sends a request to the server that hosts the website. The server then responds by sending the requested information back to your computer. This process is known as communication between a client and a server.
In order to ensure that communication is successful, both the client and the server must follow certain rules, or protocols. One of the most important protocols is the Hypertext Transfer Protocol (HTTP), which governs how webpages are transmitted on the internet.
HTTP is a “stateless” protocol, which means that each request is treated independently from all other requests. This is different from “stateful” protocols, where each request is linked to the previous request. In order for a server to keep track of stateful information, it must use cookies.
Cookies are small pieces of data that are stored on your computer by the website you visit. They are used to remember information about you, such as your login details or preferences. Cookies are important because they allow websites to provide you with a personalized experience.
Some cookies are essential for the operation of the website, while others are used for marketing purposes. You can usually control which cookies are used by changing your browser settings. However, some cookies are necessary in order for the website to function properly, so it is not recommended that you disable them.
7. nslookup
NSlookup is a network administration command-line tool for querying the Domain Name System (DNS) to obtain domain name or IP address mapping, or other DNS records. NSlookup can be used interactively or in batch mode by specifying the records to query for on the command line.
The output of NSlookup depends on the operating system. For example, on Windows, the default output is in a human-readable format, while on Linux, the default output is in a machine-readable format.
8. iptables
Iptables is a command line utility used to set up, maintain, and inspect the tables of IP packet filter rules in the Linux kernel. The main purpose of iptables is to provide firewall functionality. Iptables uses a set of tables which contain chains of rules for handling packets.
9. tcpdump
TCPdump is a powerful network monitoring and data analysis tool. It can be used to capture and analyze network traffic in real time. TCPdump is available for free and is widely used by network administrators and security professionals.
10. nmap
Nmap is a network exploration and security auditing tool. It can be used to identify hosts and services on a network, as well as security issues. Nmap is free and open source.
Nmap can be used to scan for vulnerable open ports on systems. This can be used to find systems that are vulnerable to attack. Nmap can also be used to fingerprint operating systems and services. This can be used to identify which systems are running which software. Nmap can also be used to scan for wireless access points and devices.
Nmap is a powerful tool that can be used for both network exploration and security auditing. It is free and open source, making it a great choice for many users.