--- asterisk-12.2.0/channels/chan_sip.c 2014-04-21 17:02:00.000000000 -0400
+++ asterisk-12.2.0-modified/channels/chan_sip.c        2014-05-24 12:43:53.816120532 -0400
@@ -24024,6 +24024,29 @@
                sip_publish_registry(r->username, r->hostname, regstate2str(r->regstate));
                r->regattempts = 0;
                ast_debug(1, "Registration successful\n");
+
+               //Get PEER from Realtime subsystem, and if peer exist, update field with useragent, ipaddr, port, ...
+               struct sip_peer *peer;
+               const char *useragent;
+               peer = sip_find_peer(r->peername, NULL, TRUE, FINDPEERS, FALSE, 0);
+               //Peer can be not available in case of use "register=>" in 'sip.conf' and not in 'sippeers' table with 'callbackextension' field
+               if(peer) 
+               {
+                       ao2_lock(peer);
+                       set_peer_nat(p, peer);
+                       ast_copy_flags(&p->flags[0], &peer->flags[0], SIP_NAT_FORCE_RPORT);
+                       parse_register_contact(p,peer,req);
+
+                       //Parse User Agent (Server Header)
+                       useragent = sip_get_header(req, "Server");
+                       if (strcasecmp(useragent, peer->useragent)) {
+                               ast_string_field_set(peer, useragent, useragent);
+                               ast_verb(4, "Saved useragent \"%s\" for peer %s\n", peer->useragent, peer->name);
+                       }
+                       update_peer(peer, p->expiry);
+                       ao2_unlock(peer);
+               }
+
                if (r->timeout > -1) {
                        ast_debug(1, "Cancelling timeout %d\n", r->timeout);
                }