Index: chan_sip.c
===================================================================
--- chan_sip.c	(revision 25382)
+++ chan_sip.c	(arbetskopia)
@@ -1215,7 +1215,7 @@
 	unsigned int profile = 0;
 	int i, found;
 
-	if (!pvt || ast_strlen_zero(supported) )
+	if (ast_strlen_zero(supported))
 		return 0;
 
 	if (option_debug > 2 && sipdebug)
@@ -1241,7 +1241,8 @@
 			ast_log(LOG_DEBUG, "Found no match for SIP option: %s (Please file bug report!)\n", next);
 	}
 
-	pvt->sipoptions = profile;
+	if (pvt)
+		pvt->sipoptions = profile;
 	return profile;
 }
 
@@ -5237,7 +5238,7 @@
 	other end knows and replace the current call with this new call */
 	if (p->options && p->options->replaces && !ast_strlen_zero(p->options->replaces)) {
 		add_header(&req, "Replaces", p->options->replaces);
-		add_header(&req, "Required", "replaces");
+		add_header(&req, "Require", "replaces");
 	}
 
 	if (p->options && !ast_strlen_zero(p->options->distinctive_ring)) {
@@ -10982,7 +10983,7 @@
 	}
 
 	/* Find out what they require */
-	required = get_header(req, "Required");
+	required = get_header(req, "Require");
 	if (!ast_strlen_zero(required)) {
 		required_profile = parse_sip_options(NULL, required);
 		if (required_profile) { 	/* They require something */
@@ -11801,6 +11802,11 @@
 			RFC 3261 - section 12.2 - and we don't want to mess with recovery  */
 		if (!p->initreq.headers && ast_test_flag(req, SIP_PKT_WITH_TOTAG)) {
 			/* If this is a first request and it got a to-tag, it is not for us */
+			if (req->method == SIP_ACK) {
+				ast_log(LOG_DEBUG, "Ignoring ACK\n");
+				return res;
+			}
+
 			if (!ast_test_flag(req, SIP_PKT_IGNORE) && req->method == SIP_INVITE) {
 				transmit_response_reliable(p, "481 Call/Transaction Does Not Exist", req);
 				/* Will cease to exist after ACK */