DHCP overwrites Cisco VPN resolv.conf on Linux

Question

I'm using an Ubuntu 8.04 (x86_64) machine to connect to my employer's Cisco VPN. (The client didn't compile out of the box, but I found patches to update the client to compile on kernels released in the last two years.) This all works great, until my DHCP client decides to renew its lease and updates /etc/resolv.conf, replacing the VPN-specific name servers with my general network servers.

Is there a good way to prevent my DHCP client from updating /etc/resolv.conf while my VPN is active?

Answer 1

If you are running without NetworkManager handling the connections, use the resolvconf package to act as an intermediary to programs tweaking /etc/resolv.conf: sudo apt-get install resolvconf

If you are using NetworkManager it will handle this for you, so get rid of the resolvconf package: sudo apt-get remove resolvconf

I found out about this when setting up vpnc on Ubuntu last week. A search for vpn resolv.conf on ubuntuforums.org has 250 results, many of which are very related!