We run a mac network here in the office. We have an internal DNS server to manage the network. Everything is resolved to a local ip (for mail.mydomain.com etc). However, we also have an external DNS server for when our users are not in the office. However, isn't it a pain to have to manage two lists? Whenever you change something you have to change another? And you can't have one be a slave of another because the ip are sometimes different (for example mail.mydomain.com would point to a local ip in local dns server but an external ip in the external dns server). Any tricks?