I've got the following setup: SIP Client --> SER --> Asterisk --> Iptel.org SIP account I'm now trying to place an outgoing call, which has to be authenticated at the iptel.org proxy server (which ser can't do) but I seem to be getting 407 packets with the IP of the asterisk machine as realm. SIP Client SER * Iptel.org Invite -------> Invite -----> Invite -------> <--- 407 realm ip_of_* Afaik the realm iptel.org should provide to * should be "iptel.org" instead of the IP of the * box (which would indicate an error at iptel?) What I'm trying to archive is that the * box authenticated the calls to iptel and then leave the call alone (so I will have to find out how to get * out of the media path) I'm still new to all this, but I think this could work. Kind regards, E. Versaevel Extensions.conf [sip_in_from_carrier] exten => _XXXXXXXXXX, 1, Dial(SIP/${EXTEN}@${SERADDRESS},20,r) ;Not a 10 digit number exten => s,1,Answer exten => s,2,MusicOnHold() exten => s,3,Hangup ;Timeout exten => t,1,Answer exten => t,2,Background(conf-invalid) ;exten => t,3,MusicOnHold() exten => t,4,Hangup ;Hangup exten => h,1,Hangup [sip_in_from_ser] exten => _., 1, Dial(SIP/${EXTEN}@sip.carrier,20,r) ;Not a 10 digit number exten => s,1,Answer exten => s,2,MusicOnHold() exten => s,3,Hangup ;Timeout exten => t,1,Answer exten => t,2,Background(pin-invalid) ;exten => t,3,MusicOnHold() exten => t,4,Hangup ;Hangup exten => h,1,Hangup [default] exten => s, 1, Background(conf-invalid) exten => s, 2, Hangup Sip.conf [general] port=5065 disallow=all allow=ulaw register => asterisk:asterisk@sermachine ;Incomming from ser register => iptel:iptel@sip.iptel.org/iptel_alias ;Incomming from iptel [sip.carrier] type=user realm=iptel.org username=iptel secret=iptel host=sip.iptel.org canreinvite=no context=sip_in_from_carrier [sip.carrier] type=peer host=sip.iptel.org context=sip_in_from_carrier [sip.ser] type=user realm=sermachine host=sermachine canreinvite=no context=sip_in_from_ser [sip.ser] type=peer host=sermachine context=sip_in_from_ser