Ping: unknow host but can ping IPs

January 30, 2016 6.2k views
DNS DigitalOcean Ubuntu

After restarting my droplet [Ubuntu 15.10 x64], I keep getting "unknown host" message. Pinging IPs though works fine.

I cannot cat resolv.conf, it says "No such file or directory" although on ls -l it does appear as a linked file to /run/resolvconf/resolv.conf. which I cannot access either - no resolvconf folder in run dir.

In /etc/network/interfaces, I have dns-nameservers 8.8.8.8 8.8.4.4 under eth0.

Sorry if any of the above information is irrelevant, I am a Linux noob.
Any help would be greatly appreciated!

7 comments
  • Note: your system probably requires you to use 'sudo' in front of your privilege access commands, or need to issue 'su root' to gain full root access. Try

    sudo cat /etc/resolve.conf 
    

    So, reboot cleared out your DNS cache and now your DNS servers have gone dark. Can you ping IP address 8.8.8.8 or 8.8.4.4 ?

  • I always log in with root, but tried sudo cat /etc/resolve.conf anyway. The result is the same "No such file or directory".

    I can ping both 8.8.8.8 and 8.8.4.4. I can also ping the gateway.

    One additional note though, I was playing around with ufw before restarting the droplet. However, after discovering this issue, I have inactivated it, but the problem persists.

  • @medowlock - Does your system have a /var/run/resolvconf/resolv.conf
    If it's there, for diagnostic purpose, create a link to it in etc

    ln -s /var/run/resolvconf/resolv.conf /etc/resolv.conf
    

    Then try ping digitalocean.com

  • This is where it gets really weird, at least for me. When listing the contents of /etc I can see there is a file resolv.conf symlinked to /run/resolvconf/resolv.conf. However

    root@ubuntu-512mb-fra1-01:/run# cd /run/resolvconf
    -bash: cd: /run/resolvconf: No such file or directory
    

    And running the command you mentioned gives

    root@ubuntu-512mb-fra1-01:~# ln -s /var/run/resolvconf/resolv.conf /etc/resolv.conf
    ln: failed to create symbolic link ‘/etc/resolv.conf’: File exists
    root@ubuntu-512mb-fra1-01:~# cat /etc/resolv.conf
    cat: /etc/resolv.conf: No such file or directory
    
    root@ubuntu-512mb-fra1-01:~# ping digitalocean.com
    ping: unknown host digitalocean.com
    

    Thanks for all your answers and patience!

  • @medowlock - Oops, need to remove the existing file before the link command:

    mv /etc/resolv.conf /etc/resolv.conf.hold
    ln -s /var/run/resolvconf/resolv.conf /etc/resolv.conf
    
  • Show 2 more comments
1 Answer

This question was answered by @medowlock:

@gndo No luck.

But I did manage to get it working again. What I did was remove the symlink altogether and created the resolv.conf file manually and added to its contents:

nameserver 8.8.8.8
nameserver 8.8.4.4

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