SetUp: - Asterisk behind a NAT, - Red Hat 9.0 - Asterisk 1.2.14 My Asterisk box is behind a NAT and I have a DiD from an ITSP. I have my dial plan set up so that when outside callers dial the DiD, the call is answered by my auto-attendant. The caller can then select who they'd like to speak to and the call is transferred to the external line associated with that person (usually a mobile phone) using a Dial() command. Because both parties are external, I don't want the media to pass through my Asterisk box once the two parties connect. This is the default behaviour for the Dial command if you avoid the tT options and the codec is supported all the way through - this is true in my case. I have this working great with IAX - I can even disconnect the Ethernet cable from my Asterisk box once the call is established and the call is not affected. Unfortunately I cannot get it to work with SIP and my ITSP is dropping support for IAX. Can you help me? I've attached the relevant bits from sip.conf. I have canreinvite=yes and I've tried with nat=yes and nat=no, but no luck either way - the call goes through in each case but the media is passing through my Asterisk box and i'd like to avoid that. Anxiously awaiting a reply. Thanks, H register => me: xxxx@my1.itsp.com:5060 register => me: xxxx@my2.itsp.com:5060 ; This section is because i'm behind nat ; externip=999.999.999.999 ;Outside address localnet= 192.168.0.148/255.255.255.0 ;Inside Network ; ;===========================================================; [voip-ITSP1] context=incoming-sip type=friend host= my1.itsp.com username=me secret=xxxxxxx nat=no canreinvite=yes insecure=port,invite ; do NOT remove this qualify=yes ; do NOT remove this dtmfmode=rfc2833 ; should match what is set on your account disallow=all allow=ulaw ; set in/out codec here ; [voip-ITSP2] context=incoming-sip type=friend host= my2.itsp.com username=me secret=xxxxxxx nat=no canreinvite=yes insecure=port,invite ; do NOT remove this qualify=yes ; do NOT remove this dtmfmode=rfc2833 ; should match what is set on your account disallow=all allow=ulaw ; set in/out codec here