The following ports needed to be forwarded to the asterisk server for various remote access

Port 80 (Freepbx web access)
Port 4445 (Flash Operator Panel web access)
Port 4569 (IAX remote phone clients)
Port 5059-5061 (registration and proxy server access, default is 5060)
Port 10000-10025 (ports reserved for RTP voice packets for SIP phone conversations)