--- chan_sip.c	2005-05-19 23:14:41.000000000 -0400
+++ channels/chan_sip.c	2005-05-20 16:26:56.275571733 -0400
@@ -3516,7 +3516,8 @@
 /*--- respprep: Prepare SIP response packet ---*/
 static int respprep(struct sip_request *resp, struct sip_pvt *p, char *msg, struct sip_request *req)
 {
-	char newto[256] = "", *ot;
+	char newto[256] = "";
+	char  *ot;
 
 	memset(resp, 0, sizeof(*resp));
 	init_resp(resp, msg, req);
@@ -3573,6 +3574,7 @@
 	char newto[256];
 	char *c, *n;
 	char *ot, *of;
+	int is_strict = 0;	/* Strict routing flag */
 
 	memset(req, 0, sizeof(struct sip_request));
 	
@@ -3587,17 +3589,27 @@
 		p->branch ^= rand();
 		build_via(p, p->via, sizeof(p->via));
 	}
+
+	/* Check if next hop is a strict route */
+	if (p->route && !ast_strlen_zero(p->route->hop) && strstr(p->route->hop,";lr") == NULL) {
+		is_strict = 1;  /* Strict route indeed, sir */
+	}
+
 	if (sipmethod == SIP_CANCEL) {
 		c = p->initreq.rlPart2;	/* Use original URI */
 	} else if (sipmethod == SIP_ACK) {
 		/* Use URI from Contact: in 200 OK (if INVITE) 
 		(we only have the contacturi on INVITEs) */
-		if (!ast_strlen_zero(p->okcontacturi))
-			c = p->okcontacturi;
+
+		c = p->route->hop;
+
+/*		if (!ast_strlen_zero(p->okcontacturi))
+			c = is_strict ? p->route->hop : p->okcontacturi;
 		else
 			c = p->initreq.rlPart2;
+*/
 	} else if (!ast_strlen_zero(p->okcontacturi)) {
-		c = p->okcontacturi; /* Use for BYE, REFER or REINVITE */
+		c = is_strict ? p->route->hop : p->okcontacturi; /* Use for BYE or REINVITE */
 	} else if (!ast_strlen_zero(p->uri)) {
 		c = p->uri;
 	} else {
@@ -3626,6 +3638,11 @@
 	add_header(req, "Via", p->via);
 	if (p->route) {
 		set_destination(p, p->route->hop);
+
+		if (is_strict)
+			add_route(req, p->route->next);
+		else
+			add_route(req, p->route);
 		add_route(req, p->route->next);
 	}