I see that there are alot of posts for this issue, and we just ran into this issue. We were able to resolve it, so I wanted to publish the notes.
If you are running a Cisco VPN client that is 5.0.3.xxxx or higher, then our solution might help you with your issue.
With the rollout of 5.0.3.03xx (not sure exactly if it was 0340 or 0390), Cisco has enabled IPV6 on the Cisco VPN adapter. Whether or not your network adapter has this enabled or not, the Cisco VPN adapter will enable it. In our situation, it affected DNS. Our DNS servers were appearing as IPV6 addresses, when looking at the IPCONFIG /ALL under the VPN adapter. Our Cisco ASA and Cisco Routers are not IPV6 enabled.
To resolve this, we went into network, right clicked on Cisco VPN adapter, went to properties, and unchecked the IPV6 box. Clicked okay to get all the way out, and retried the VPN connection. Our DNS servers now appear as IPV4 and DNS resolution has been restored.
I hope this helps anyone still looking for a resolution to this issue.
Regards,
Jay McMickle
CCNA,CCSA,CCA,MCSE
Houston, TX.