Hello, Could someone tell me if I understand this correctly please. file src/mod/endpoints/mod_sofia/mod_sofia.c line 1021 in case SWITCH_MESSAGE_INDICATE_RESPOND which is what is used by the "respond" function, The domain used to create the challenge is "sip_to_host", which is good when I want to challenge a message DESTINED to the machine itself, however not great if you want to challenge a message to another domain routed through the dialplan like explained on http://wiki.freeswitch.org/wiki/Misc._Dialplan_Tools_respond . When I am calling 888@conference.freeswitch.org, with my phone me@domain.com , I challenge the call in the dialplan with a "respond" "407" which sent me back user="me" realm="conference.freeswitch.org" due to sofia_reg_auth_challenge(NULL, tech_pvt->profile, tech_pvt->nh, REG_INVITE, to_host, 0); Is it a bug ? Should it really be "from_host". Can it be changed without breaking existing installation ? Thomas Mangin -- Exa Networks Limited - http://www.exa-networks.co.uk/ Company No. 04922037 - VAT no. 829 1565 09 27-29 Mill Field Road, BD16 1PY, UK Phone: +44 (0) 845 145 1234 - Fax: +44 (0) 1274 567646