A few months ago I downloaded example config files, as a way to learning openser, but I'm not 100% sure where I got them. One of them has this header: # $Id: nat-rtpproxy.cfg 9 2005-08-19 15:30:55Z /CN=Greger V. Teigre/emailAddress=greger(a)onsip.org $ I just found (re-found?) at onsip.org->downloads->Getting Started, a later version of nat-rtpproxy.cfg with this header: # $Id: nat-rtpproxy.cfg 51 2006-01-31 13:28:04Z /CN=Paul Hazlett/emailAddress=paul(a)onsip.org $ and they appear different only in the loose_route handling: OLD: if (loose_route()) { if (has_totag() && (method=="INVITE" || method=="ACK")) { if (nat_uac_test("19")) { setflag(6); force_rport(); fix_nated_contact(); }; force_rtp_proxy("l"); }; route(1); break; }; NEW: if (loose_route()) { if ((method=="INVITE" || method=="REFER") && !has_totag()) { sl_send_reply("403", "Forbidden"); break; }; if (method=="INVITE") { if (!proxy_authorize("","subscriber")) { proxy_challenge("","0"); break; } else if (!check_from()) { sl_send_reply("403", "Use From=ID"); break; }; consume_credentials(); if (nat_uac_test("19")) { setflag(6); force_rport(); fix_nated_contact(); }; force_rtp_proxy("l"); }; route(1); break; }; Now, who wants to take a stab at explaining why this was changed? Why was ACK checked for in the old version and not the new? (my guess: zero length message body messes with force_rtp_proxy) Why does that INVITE logic appear in the new loose_route handler? What case does that handle that the later "if (method == INVITE)" doesn't handle? Does this have something to do with re-INVITES? For convenience, the two files are here: http://a.mainstreet.net/nat-rtpproxy.5.0.cfg http://a.mainstreet.net/nat-rtpproxy-2006.cfg And do we openser people have our own set of sample config files somewhere on openser.org? Thanks, -mark