I use a VPN client to access my company's intranet. It used to work fine with older versions of Ubuntu. But on 12.04 it doesn't. It is able to connect but I do not see any packet exchange happening, hence not able to browse the Intranet.

During some troubleshooting I found out that in 12.04 DNS resolution has been changed, and my VPN client is not able to update the DNS server. After a little Googling I found a post which proposed adding the DNS nameserver IP addresses to /etc/dhcp/dhclient.conf as follows.

prepend domain-name-servers <ip1>, <ip2>;   #this was the addition i made



request subnet-mask, broadcast-address, time-offset, routers,

    domain-name, domain-name-servers, domain-search, host-name,

    netbios-name-servers, netbios-scope, interface-mtu,

    rfc3442-classless-static-routes, ntp-servers,

    dhcp6.domain-search, dhcp6.fqdn,

    dhcp6.name-servers, dhcp6.sntp-servers;

This resolves the issue and I can browse the intranet website. But this doesn't persist for a longer time. It appears the DNS gets changed after a while. Is there a way I can make DNS settings not to change, or every time it changes it should get those IP addresses also included ?