I’m facing basicly the same problem as descdibed here:
But with difference that I have correct SDP.
I determine that the poblem is causing because of setting of default GW. By that I mean:
I have one interface for example eth1 with acces to internet and with set GATEWAY parameter in /etc/sysconfig/network-scripts/ifcfg-eth1
and also I have enother interface eth2 which has been using only for phones and with no GATEWAY
and FROM header has displaying eth1 IP instead eth2 IP.
but I need that FROM header displaysIP of eth2.
CONTACT header is right.
So if I change GW (comment in eth1 and type some GW IP to eth2 settings) it displays the correct FROM header.
The problem is that eth2 must not have the GW.
I would suggest that investigating why someone told you you need a network connection with no configured gateway might be a good first start into this issue.