13 Jan
2005
13 Jan
'05
9:46 p.m.
The second one is for nat. For internal calls, there is no nat issue.
For
external calls, the router can be sit on both inside and outside on the network. You can avoid the nat issue on SIP messages.
NAT issues can be solved using the ip_conntrack_sip kernel module which is included in OpenWRT (it's not compiled by default, but a friend of mine built a new kernel and it works fine (no STUN or rtpproxy needed any more)
This sip ALG has some problems. It is work ok with one phone behind NAT, but not multiple phones. SIP is very complicated; probably part of reason why there is no SIP conntrack module available in POM yet.
Richard