Linux – Regenerating /etc/resolv.conf

linuxUbuntu

I'm running Ubuntu 12.04 and I managed to stomp on my /etc/resolv.conf file. I believe this is the cause of me getting

ping: unknown host www.google.com

It says resolv.conf is auto generated but I cannot figure out how to regenerate this file back to its previous default settings. I've checked many forums and the man files and I am stuck.

Appreciate any help.

Best Answer

If you don't have a copy of it, simply recreate the /etc/resolv.conf like this:

echo "nameserver 8.8.8.8" >> /etc/resolv.conf

You can add more nameservers as necessary, one per line. This example uses Google's public DNS servers. That should get you back on your feet. In the future, you should look at using revision control like Git for your configuration files (pretty much everything in /etc and whatever other software you install), and eventually evolving to proper configuration management like Puppet or Chef.

Related Solutions

Linux – Difference between /etc/hosts and /etc/resolv.conf

resolv.conf specifies the nameservers for resolver lookups, where it will actually use the DNS protocol for resolving the hostnames.
Typically the hosts file is used for administrative purposes, such as backend and internal functions, which is substantially more isolated in scope, as only the local server will reference it.

/etc/nsswitch.conf specifies the lookup order with the hosts entry.

If this does not answer your question, please clarify further.

Look at the following manpages:

HOSTS(5)  
RESOLVER(5)

Linux – sendmail – custom /etc/resolv.conf and /etc/hosts files

In short, not that I know of. Most programs use standard system calls for any name resolution and leave the details to the OS.

Now, if you're concerned about people/programs changing file contents, take a look at the chattr command. You can set files such that they can't be overwritten without removing the immutable flag first. It's highly unlikely any program will be written to do that.

Best Answer

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Linux – Difference between /etc/hosts and /etc/resolv.conf

Linux – sendmail – custom /etc/resolv.conf and /etc/hosts files

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