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Community Member

port redirection for RTP with PAT

With PAT on a PIX version 6.22 (overloading the outside interface) and redirecting RTP upd ports 16384-32767 to an ATA 186 for VOIP - isn't it likely to break applications on other internal devices that are receiving packets with udp ports in that range?

Cisco Employee

Re: port redirection for RTP with PAT

No, it should not. The UDP port numbers on the inside and outside do not have to (and much of the time do not) match.

Community Member

Re: port redirection for RTP with PAT

Thanks for the information. It prompted me to rethink the relationship between SIP, RTP, and NAT. Please let me know if you agree with how I see it now: Any outside-initiated phone call will be to tcp port 5060. A static from the outside ip address to the inside ATA 186 ip address for tcp port 5060 should be all that's needed. After that the NAT table will have an Address:Port table (unrelated to the port redirection) for that call. Port redirection in the static is pro forma, required only because of PAT. No other port redirection should be required.

The config is: static (inside,outside) tcp 5060 5060

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