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6 ways to fix network issues in Linux

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Network issue is a common problems that can occur in any operating system, but it can be especially frustrating on Linux systems. In this blog post, we will discuss six ways to troubleshoot network issues in Linux. We will also provide insights from a system administrator who has experience dealing with this issue. Let’s get started!

check physical network cable to fix network problems in Linux

If you are experiencing network packet loss, the first thing you should check is the physical network cable. Make sure that it is properly connected and that there are no kinks in the cable. If the cable is damaged, you will need to replace it.

If the physical network cable is not the issue, you can try restarting the network interface. This can be done by running the following command: sudo ifdown eth0 && sudo ifup eth0

replace “eth0” with your actual network interface name.

run ifconfig to check for IP address conflict in Linux

Another common cause of network issues is an IP address conflict. To check for this, run the ifconfig command. This will display your network interfaces and their corresponding IP addresses. If you see any conflicts, you will need to resolve them.

One way to do this is by using the ifconfig command. This will allow you to change the IP address of your network interface. sudo ifconfig eth0 192.168.1.100

replace “eth0” with your actual network interface name, and replace “192.168.1.100” with the desired IP address.

use tcpdump to troubleshoot network packets in Linux

If you are still experiencing network issue, you can use tcpdump to troubleshoot the issue. Tcpdump is a command-line tool that allows you to capture packets on your local system. This can be helpful in determining where the problem is occurring.

To use tcpdump, run the following command:

sudo tcpdump -i eth0 -w /tmp/packet-loss.pcap port 8080 and host 192.168.0.100

replace “eth0” with your actual network interface name, and replace “192.168.0.100” with the IP address of the remote host. This will save the packets to a file called /tmp/packet-loss.pcap.

Check this post to get more advanced examples on how to capture packets with tcpdump command.

Once you have captured the packets, you can use a tool like Wireshark to inspect them. This will allow you to see what is causing the packet loss.

change kernel parameter to fix network problem in Linux

Another common cause of network issue is a problem with the TCP window. You can fix this problem by changing the kernel parameter tcp window.

The net.core.wmem_max kernel parameter sets the maximum size of the send buffer for a socket. This parameter can be helpful in resolving network packet loss issues.

To change this parameter, you will need to edit the /etc/sysctl.conf file. You can do this with the following command: sudo nano /etc/sysctl.conf

You will then need to add the following line to the file: net.core.wmem_max=16777216

save and close the file, then run the following command to apply the changes: sudo sysctl -p

This should fix the network packet loss issue. If you are still experiencing problems, you can try increasing the value of this parameter.

change mtu size to fix packet loss in Linux

If you are experiencing network packet loss, you may be able to fix the problem by changing the MTU size.

MTU size is the maximum packet size that can be transmitted on a network. If the packet size is larger than the MTU size, the packet will be fragmented into multiple packets. This can cause problems with networking applications.

This can be done by editing your /etc/sysctl.conf file and adding the following line: net.ipv4.ip_mtu=1492

After making this change, you will need to restart your computer for it to take effect.

update your kernel to fix network issues in Linux

Finally, if all else fails, you may need to update your kernel. This can be a time-consuming process, but it may be necessary in order to fix network packet loss.

To update your kernel, you will need to download the latest version from the Linux Kernel website. Once you have downloaded the kernel, you will need to extract it and install it.

For more detailed instructions, you can refer to the Kernel documentation.

These are six ways that you can fix network problem in Linux. If you are still having problems, you may need to contact your system administrator for help. Thank you for reading!

David Cao
David Cao

Hey there! I am David, a Cloud & DevOps Enthusiast and 18 years of experience as a Linux engineer. I work with AWS, Git & GitHub, Linux, Python, Ansible, and Bash. I am a technical blogger and a Software Engineer, enjoy sharing my learning and contributing to open-source.