[Freeswitch-users] Yet another NAT question

Hi, Since several people have suggested to avoid SIP ALG at all costs, I have disabled it and banged my head some more! Without SIP ALG, only one of my Polycom 335s can Register. The other 5 fail. (With SIP ALG they all register fine). Now I have found that changing: SETTINGS>SIP>LOCAL SIP PORT> to a UNIQUE port (5066 in this case) And SETTINGS>NETWORK>NAT>SIGNALING PORT> to the same UNIQUE port I got a second phone to REGISTER and exchange calls! When I say unique port, I mean unique to all the phones on this NAT Router. My question is "Is that fine?" I just want to know if there are limitations on the SIP Port number? Are there issues I should watch out for. Thanks, Sean