[Asterisk-Users] SIP x NAT

[Eric Wieling]

>> I have a question for you:
>>
>> - "SIP doesn't work behind NAT very well"
>>
>> Do you agree with this sentence?

Complete and utter crap (if you assume a few things).

SIP w/NAT works just fine if:
   Asterisk itself is not behind NAT
   You do not want to use SIP reinvites
   You use some form of NAT Keepalive*
   You use nat=yes in sip.conf
   Your NAT router is not SIP aware

If your NAT router is SIP aware then you can 1) turn off it's SIP 
awareness and treat it like a dumb NAT router or 2) enable it's SIP 
awareness and turn off nat=yes in sip.conf.  A SIP aware router might 
make reinvites work of both SIP clients have a SIP aware router.

* You can keep your NAT alive by using a registration of 60 seconds on 
the NAT device, or use qualify=yes in sip.conf, or use the NAT 
Keepalive features of your SIP device.