no resolv.conf on core and MD and MD doesn't have DNS.
on the core Bind9 is running but resolv.conf is empty. resolv.conf example for the core:
Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 192.168.80.1 search LinuxMCE nameserver 8.8.8.8
resolv.conf example for the MD: Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 192.168.80.1