[Ekiga-devel-list] STUN usage with SIP

[schwatzi web de]

Hi,

How does STUN work in ekiga?

STUN is normaly used as followed:
The STUN client should use the same socket as SIP and the received IP 
and Port should then be used for constructing Contact- , Via- field and SDP.
Then a keepalive is needed to keep the NAT Session in the router alive ( 
to refresh the mapping table entry).
This could be a done in many ways.
1. sending registers more frequently
2. sending empty SIP packets
3. sending SIP Request like OPTIONS or NOTIFY(Event: keepalive).
A STUN Request should be done frequently in case the public address (IP 
or port) changes( i.e. after a router restart )

Looking at Ekiga
- it uses a different socket for SIP and STUN ( therefor it cannot use 
the discovered port to build the contact SIP packets. So a user needs to 
configure his router, too. i.e. Portforwarding or SIP-ALG)
- it adds the public IP in the contact but doesn't change the Via.
- it only sends one STUN Request when registering, and don't updates its 
public address
- it has no keepalive


regards