Hmmmm. When it comes to firewall rules there seems to be two camps: those who create rules such as "allow TCP traffic from my pc on port b to server x on port y" and those who put a server in the trusted zone and just allow any traffic to and from it. I don't see any benefit in doing the former - very controlling behaviour
Also very inflexible. I do the latter - all my mail servers, proxy server, DNS, DHCP, NNP, NTP, UBR, SETI, various FTP servers, and the CM subnet are in the trusted zone along with localhost.