I am running Ubuntu 12.04 on my server but since the upgrade from 10.04 I can no longer reach any outside sources of the server.

I can SSH into the box, but from inside here I can not reach anything. At least, I can't ping, dig etc.

I have provided everything that I could think that might give me more information, but can't see anything obviously wrong here.


 root@sub:~# resolveip google.com
 resolveip: Unable to find hostid for 'google.com': try again


 root@sub:~# ping google.com
 ping: unknown host google.com

route -n

 root@sub:~# route -n
 Kernel IP routing table
 Destination     Gateway         Genmask         Flags Metric Ref    Use Iface         UG    100    0        0 eth0   U     0      0        0 eth0

iptables -L

 root@sub:~# iptables -L
 Chain INPUT (policy ACCEPT)
 target     prot opt source               destination

 Chain FORWARD (policy ACCEPT)
 target     prot opt source               destination

 Chain OUTPUT (policy ACCEPT)
 target     prot opt source               destination

Any ideas what has changed since the upgrade?

up vote 5 down vote accepted

First try to ping your gateway If you are able to do so, then

I think /etc/resolv.conf is not properly configured.

Just open /etc/resolv.conf file . At the top of that file, add a line like this:


This is the resolver to which all DNS resolution requests will be directed to. and are the two open-resolvers which anyone can use.

After this, you should be able to ping google.com.

  • 1
    blow me down, it worked :) Another problem then, I am trying to install plesk for a client. But the server won't hit: gb.archive.ubuntu.com/ubuntu but when using a browser the page opens perfectly. If i ping above it returns host unknown. Any ideas? Been trying for 2 days. – Jamie Hutber Mar 31 '13 at 10:05
  • @JamieHutber you are doing mistake here. You should execute ping gb.archive.ubuntu.com but not ping gb.archive.ubuntu.com/ubuntu. Can you explain me how are you trying to install plesk ? Are you using some package manager. – pradeepchhetri Mar 31 '13 at 10:13
  • is another big public DNS server. – goldilocks Mar 31 '13 at 10:58
  • Ye sorry, I am using ping gb.archive.ubuntu.com not with the trailing ubuntu. So i am trying to install ubuntu using the autoinstaller. The problem I get is 500 http://gb.archive.ubuntu.com/ubuntu/ hardy/main i386 Packages release v=8.04,o=Ubuntu,a=hardy,n=hardy,l=Ubuntu,c=main origin gb.archive.ubuntu.com I follow all of the steps, it adds autointall.plesk.com into my apt-get package. Then as you see gives me a 500 error when trying to download. Been working on it for 2 days now :( – Jamie Hutber Mar 31 '13 at 11:01
  • 1
    @JamieHutber ping is not the correct utility to check reachability because ICMP packets may be blocked in many cases. Instead use tcptraceroute www.cnn.com 80. This will check the connectivity to 80 port of cnn.com – pradeepchhetri Mar 31 '13 at 14:03

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