Well this issue is not expected to be seen by many as it is particular scenario where the issue arises.

If your network has IPv4 DHCP and IPv6 DHCP enabled then you may see this issue.

Your newly installed off the CD ubuntu 11.10 requests and receives both an IPv4 and a IPv6 address making your freshly installed system a dual stacked one.

You would think that having both IPv4 and IPv6 would make IP communications possible with a wider audience than a simply IPv4 or IPv6 only system. In reality you get the same connectivity as a native IPv6 attached host, Why?

Well as ubuntu ONLY adds IPv6 DNS server entries from the DHCP information received to /etc/resolv.conf this causes an issue whereby standard sites that do not operate IPv6 are not accessible. The simply answer is to add a new nameserver entry for your IPv4 DNS servers.

This does mean as a side effect that even if you only have two name servers per IP stack, it can cause slow response when a DNS server has failed, to help combat this I use the following line at the end my resolv.conf file.

options timeout:1 attempts:2 # reduce DNS timeout to 3 seconds

My full /etc/resolv.conf file looks similar to this:

domain example.com
search example.com
nameserver 2001:470:1::6
nameserver 2001:470:2::8
nameserver 192.168.0.6
nameserver 192.168.254.8
options timeout:1 attempts:2 # reduce DNS timeout to 3 seconds