diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index c9b6ab39e2..1968609a04 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -10230,13 +10230,20 @@ static int transmit_register(struct sip_registry *r, int sipmethod, const char *
 		else
 			snprintf(to, sizeof(to), "<sip:%s@%s>", r->username, p->tohost);
 	}
-
-	/* Host is what we are registered to, regardless if a domain exists in the username */
-	if (r->portno && r->portno != STANDARD_SIP_PORT)
-		snprintf(addr, sizeof(addr), "sip:%s:%d", r->hostname, r->portno);
-	else
-		snprintf(addr, sizeof(addr), "sip:%s", r->hostname);
-
+	
+	/* Fromdomain is what we are registering to, regardless of actual
+	   host name from SRV */
+	if (!ast_strlen_zero(p->fromdomain)) {
+		if (r->portno && r->portno != STANDARD_SIP_PORT)
+			snprintf(addr, sizeof(addr), "sip:%s:%d", p->fromdomain, r->portno);
+		else
+			snprintf(addr, sizeof(addr), "sip:%s", p->fromdomain);
+	} else {
+		if (r->portno && r->portno != STANDARD_SIP_PORT)
+			snprintf(addr, sizeof(addr), "sip:%s:%d", r->hostname, r->portno);
+		else
+			snprintf(addr, sizeof(addr), "sip:%s", r->hostname);
+	}
 	ast_string_field_set(p, uri, addr);
 
 	p->branch ^= ast_random();