Prior to 12.04 when using Ubuntu as a gateway server for LANs I would setup systems
as router, firewall, DHCP server and private DNS server for LAN and caching. The WAN (red) eth0 interface DHCP from the ISP and LAN (green) eth1 is static 192.168.1.1. To setup my forwarders for DNS server I created a hook script in dhclient-enter-hooks.d that when eth0 goes up:
1. grabbed the ISP nameservers from $new_domain_name_servers
2. format and write nameservers to /var/cache/bind/ fowarders which is an include in named.conf.options
3. reload bind to get forwarders config
4. override make_resolv_conf() to set the resolv.conf with LANs domain and nameserver and not the ISP's since anything outside the LAN will be forwarded by local DNS server if not cached.
This served me well until 12.04 with resolvconf. I can still get it to work because the hook writes directly to resolv.conf removing the symbolic link which effectively disables resolvconf. So my questions are is there any consequences to this approach? Should I just uninstall resolvconf? Is there a better way to do what I wish utilizing resolvconf? So far I have not figured out how to make it work with resolvconf.