With some configurations a transport is not actually specified so assume UDP in these cases.

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Merged revisions 369490 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 369491 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@369492 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -26949,7 +26949,7 @@ int get_address_family_filter(unsigned int transport)
 {
 	const struct ast_sockaddr *addr = NULL;
 
-	if (transport == SIP_TRANSPORT_UDP) {
+	if ((transport == SIP_TRANSPORT_UDP) || !transport) {
 		addr = &bindaddr;
 	}
 	else if (transport == SIP_TRANSPORT_TCP) {