Hi All, I'm trying to understand how SIP re-invites work, if both parties are NAT'd and firewalled. I can't see how either party can initiate the conversation, and the far-end firewall would surely see any incoming packets as unsolicited, even with a STUN server giving the public IPs.. We recently moved networks, and my boss is telling me this used to work on the old network for him and his SIP phpne at home, but in the move the only thing that changed was the internal IP range, not the firewall configs etc. Cheers, Adrian