[c-nsp] experience with nat sip in 12.4(9)T and later

[Patrick Giagnocavo]

I am just wondering if the nat sip and related commands 
(http://www.cisco.com/en/US/docs/ios/ipaddr/command/reference/iad_nat.html#wp1012608) 
will do what I think they will, for a SipX server (Linux-based PBX like 
Asterisk, but SIP-only) behind a firewall. 

The idea is to have the SipX server be behind the firewall and yet still 
allow the phones, also behind the firewall, to successfully traverse the 
NAT and be able to complete SIP calls with an Internet based VOIP 
provider (which handles the PSTN termination).

Any advice would be most welcome.

--Patrick