Resolved “Temporary Failure in Name Resolution” Error in Linux

A temporary failure in name resolution is a common issue that Linux users may encounter when their system cannot resolve a hostname to an IP address. This problem can occur due to various reasons, such as network connectivity issues, DNS configuration problems, or issues with the local hosts file. In this article, we will discuss several steps you can take to troubleshoot and resolve this issue on your Linux system.

1. Check your internet connection

Before diving into the technical aspects of resolving the issue, it is crucial to ensure that your system is connected to the internet and that the network is functioning properly. Verify your system’s network connection by attempting to access a website or using the ping command to check the connectivity to a known IP address or domain.

Try to ping an IP address eg: 8.8.8.8 and see the results:

ping 8.8.8.8 -c 4 

If the ping is successful, that means internet is working properly on your system.

2. Verify DNS settings

The first step in troubleshooting temporary failure in name resolution is to verify your system’s DNS settings. The /etc/resolv.conf file contains the DNS server IP addresses, which are usually provided by your Internet Service Provider (ISP) or network administrator. This is the most common error we encouding for this error.

To view the contents of the /etc/resolv.conf file, run the following command:

cat /etc/resolv.conf 

If the file is empty or does not contain valid DNS server IP addresses, you can add them manually. To edit the file, run:

sudo nano /etc/resolv.conf 

Add the following lines with the appropriate DNS server IP addresses, such as Google’s public DNS servers:

Save and exit the file using Ctrl X, then Y, and finally Enter.

3. Check the local hosts file

The /etc/hosts file contains hostname and IP address mappings for your local system. Ensure that this file has the correct entries for your system’s hostname and IP address. You can view the file using:

cat /etc/hosts 

If the file is incorrect or missing entries, edit it using:

sudo nano /etc/hosts 

Add or correct entries as needed, following this format:

Save and exit the file.

4. Restart the network service

After making changes to the DNS or hosts files, you need to restart the networking service to apply the changes. Run one of the following commands, depending on your Linux distribution:

sudo systemctl restart networking 

or

sudo /etc/init.d/networking restart 

5. Clear the DNS cache

If your system uses a DNS caching service like nscd or dnsmasq, you should clear the cache to ensure that the latest DNS information is used. Run the appropriate command to restart the service:

sudo systemctl restart nscd 

For dnsmasq:

sudo systemctl restart dnsmasq 

6. Test the name resolution

After completing the above steps, test the name resolution using the ping, host, or nslookup commands:

ping example.com 

host example.com 

nslookup example.com 

If the issue persists after following these steps, you may need to consult your network administrator or ISP for further assistance.

Conclusion

Resolving a temporary failure in name resolution on Linux systems involves checking network connectivity, verifying DNS settings, inspecting the local hosts file, restarting network services, and clearing the DNS cache. By following the steps outlined in this article, you should be able to troubleshoot and resolve most cases of temporary failure in name resolution. However, if the issue persists, it is essential to seek help from your network administrator or ISP, as there may be underlying problems with the network infrastructure or configuration that need to be addressed.

In some cases, the issue may also be related to firewall settings or security software on your system that is blocking DNS requests. Make sure to check your firewall rules and security software settings to ensure that they are not interfering with your system’s ability to resolve hostnames.

Furthermore, it is important to keep your system updated and ensure that all packages, including DNS-related tools and services, are up to date. Regularly updating your system can help prevent issues related to outdated or incompatible software components.

By following these steps and maintaining a healthy system, you can minimize the occurrence of temporary failures in name resolution and ensure smooth operation of your Linux system on the network.