said by Trev:The only ports you need to forward are the ports you are using. It doesn't matter what anyone else is using (this includes your provider).
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You shouldn't need to forward the SIP port unless you have outside phones that need to reach your server.
Question 1: So, if I have a home asterisk implementation, and all my extensions are local to my personal private network, I wouldn't ever need to open any SIP port (say, 5060) on my router, nor would I need to forward said port to my asterisk server box and/or ATAs? That makes sense for local outbound calls.
Question 2: Same as above; but assume inbound calling to one of my DIDs from a VoIP provider. I'm registered to that provider from my asterisk box. No opening/forwarding of SIP port(s) to the * box needed? Because of my registration?
Question 3: Assume inbound calling to one of my DIDs from a VoIP provider and I'm registered to that provider direct from my ATA -- no asterisk box. No opening/forwarding of SIP port(s) to the ATA needed? Because of my registration?
Question 4: Now I'm traveling and want to connect via SIP client on my iPod to my asterisk; have that client register as an authorized extension. Is this the only situation requiring opening/forwarding of SIP port(s) to the * box? (Yes, I'm aware of "the traveling man", etc...)