Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 136523)
+++ channels/chan_sip.c	(working copy)
@@ -796,6 +796,7 @@
 #define SIP_PAGE2_BUGGY_MWI		(1 << 26)	/*!< 26: Buggy CISCO MWI fix */
 #define SIP_PAGE2_OUTGOING_CALL         (1 << 27)       /*!< 27: Is this an outgoing call? */
 #define SIP_PAGE2_UDPTL_DESTINATION     (1 << 28)       /*!< 28: Use source IP of RTP as destination if NAT is enabled */
+#define SIP_PAGE2_DIALOG_ESTABLISHED    (1 << 29)       /*!< 29: Has a dialog been established? */
 
 #define SIP_PAGE2_FLAGS_TO_COPY \
 	(SIP_PAGE2_ALLOWSUBSCRIBE | SIP_PAGE2_ALLOWOVERLAP | SIP_PAGE2_VIDEOSUPPORT | \
@@ -2108,6 +2109,7 @@
 	} else if (p->refer && !ast_test_flag(&p->flags[0], SIP_ALREADYGONE)) {
 		if (option_debug > 2)
 			ast_log(LOG_DEBUG, "Finally hanging up channel after transfer: %s\n", p->callid);
+		ast_clear_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 		transmit_request_with_auth(p, SIP_BYE, 0, XMIT_RELIABLE, 1);
 		sip_scheddestroy(p, DEFAULT_TRANS_TIMEOUT);
 	} else
@@ -3624,6 +3626,7 @@
 				if (p->vrtp)
 					videoqos = ast_rtp_get_quality(p->vrtp, NULL);
 				/* Send a hangup */
+				ast_clear_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 				transmit_request_with_auth(p, SIP_BYE, 0, XMIT_RELIABLE, 1);
 
 				/* Get RTCP quality before end of call */
@@ -3696,8 +3699,10 @@
 			if (option_debug > 1)
 				ast_log(LOG_DEBUG,"T38State change to %d on channel %s\n", p->t38.state, ast->name);
 			res = transmit_response_with_t38_sdp(p, "200 OK", &p->initreq, XMIT_CRITICAL);
+			ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 		} else {
 			res = transmit_response_with_sdp(p, "200 OK", &p->initreq, XMIT_CRITICAL);
+			ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 		}
 	}
 	ast_mutex_unlock(&p->lock);
@@ -4624,8 +4629,11 @@
 			found = (!strcmp(p->callid, callid));
 		else 
 			found = (!strcmp(p->callid, callid) && 
-			(!pedanticsipchecking || ast_strlen_zero(tag) || ast_strlen_zero(p->theirtag) || !strcmp(p->theirtag, tag))) ;
+			(!pedanticsipchecking || ast_strlen_zero(tag) || ast_strlen_zero(p->theirtag) || 
+			 !ast_test_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED) || !strcmp(p->theirtag, tag)));
 
+		ast_log(LOG_NOTICE, "Compared %s to %s\n", p->theirtag, tag);
+
 		if (option_debug > 4)
 			ast_log(LOG_DEBUG, "= %s Their Call ID: %s Their Tag %s Our tag: %s\n", found ? "Found" : "No match", p->callid, p->theirtag, p->tag);
 
@@ -12116,6 +12124,7 @@
 				return;
 
 			/* Perhaps there is an SD change INVITE outstanding */
+			ast_clear_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 			transmit_request_with_auth(p, SIP_BYE, 0, XMIT_RELIABLE, TRUE);
 		}
 		ast_clear_flag(&p->flags[0], SIP_PENDINGBYE);	
@@ -12331,6 +12340,7 @@
 		}
 		/* If I understand this right, the branch is different for a non-200 ACK only */
 		p->invitestate = INV_TERMINATED;
+		ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 		xmitres = transmit_request(p, SIP_ACK, seqno, XMIT_UNRELIABLE, TRUE);
 		check_pendings(p);
 		break;
@@ -12825,6 +12835,8 @@
 				res = handle_response_register(p, resp, rest, req, ignore, seqno);
 			else if (sipmethod == SIP_BYE)		/* Ok, we're ready to go */
 				ast_set_flag(&p->flags[0], SIP_NEEDDESTROY); 
+			else if (sipmethod == SIP_SUBSCRIBE)
+				ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 			break;
 		case 202:   /* Transfer accepted */
 			if (sipmethod == SIP_REFER) 
@@ -14513,6 +14525,7 @@
 							}
 						} else {
 							/* The other side is already setup for T.38 most likely so we need to acknowledge this too */
+							ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 							transmit_response_with_t38_sdp(p, "200 OK", req, XMIT_CRITICAL);
 							p->t38.state = T38_ENABLED;
 							if (option_debug)
@@ -14533,6 +14546,7 @@
 					}
 				} else {
 					/* we are not bridged in a call */
+					ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 					transmit_response_with_t38_sdp(p, "200 OK", req, XMIT_CRITICAL);
 					p->t38.state = T38_ENABLED;
 					if (option_debug)
@@ -14562,9 +14576,11 @@
 					}
 				} 
 				/* Respond to normal re-invite */
-				if (sendok)
+				if (sendok) {
 					/* If this is not a re-invite or something to ignore - it's critical */
+					ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 					transmit_response_with_sdp(p, "200 OK", req, (reinvite ? XMIT_RELIABLE : (ast_test_flag(req, SIP_PKT_IGNORE) ? XMIT_UNRELIABLE : XMIT_CRITICAL)));
+				}
 			}
 			p->invitestate = INV_TERMINATED;
 			break;
@@ -15205,6 +15221,7 @@
 		if (option_debug > 2)
 			ast_log(LOG_DEBUG, "Received bye, no owner, selfdestruct soon.\n");
 	}
+	ast_clear_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 	transmit_response(p, "200 OK", req);
 
 	return 1;
@@ -15463,6 +15480,7 @@
 			sip_scheddestroy(p, (p->expiry + 10) * 1000);	/* Set timer for destruction of call at expiration */
 
 		if (p->subscribed == MWI_NOTIFICATION) {
+			ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 			transmit_response(p, "200 OK", req);
 			if (p->relatedpeer) {	/* Send first notification */
 				ASTOBJ_WRLOCK(p->relatedpeer);
@@ -15479,7 +15497,7 @@
 				ast_set_flag(&p->flags[0], SIP_NEEDDESTROY);	
 				return 0;
 			}
-
+			ast_set_flag(&p->flags[1], SIP_PAGE2_DIALOG_ESTABLISHED);
 			transmit_response(p, "200 OK", req);
 			transmit_state_notify(p, firststate, 1, FALSE);	/* Send first notification */
 			append_history(p, "Subscribestatus", "%s", ast_extension_state2str(firststate));