[SR-Users] Do we need rtpproxy for all kind of NAT?

[Klaus Darilion]

On 08.05.2013 04:49, Khoa Pham wrote:
> @Olle
>
> "If you have a server on a public IP running behind Kamailio you might
> not need RTPproxy relaying for calls to and from that server. Asterisk
> will handle NAT by itself and doesn't need help if you turn on NAT
> support in Asterisk. In that case, RTPproxy just adds delay to your calls."
>
> Can you explain it a little more? Please show us the guide to do that.
> How can we not use rtpproxy in case of symmetric NAT ?

The thing is: you do not need a media relay if one of the call 
participants has a public IP address.

For example, if you have calls from SIP clients to the PSTN via a PSTN 
gateway, the PSTN gateway usually has a public IP address and therefore 
there is no need for a media relay. You only have to instruct the 
gateway to send RTP not to the IP:port announced in the SDP, but send 
RTP to the same IP:port from which the client's RTP stream is received.

If you use Asterisk as PSTN gateway, just set nat=yes in sip.conf.

regards
Klaus