diff --git a/res/res_pjsip_authenticator_digest.c b/res/res_pjsip_authenticator_digest.c
index a512b45b1bfd7a9073d7778ee47a155142d0aec9..4bc35c5ff6b2b41fcb70429c816ebe1c9da54b0c 100644
--- a/res/res_pjsip_authenticator_digest.c
+++ b/res/res_pjsip_authenticator_digest.c
@@ -206,9 +206,12 @@ static int build_nonce(struct ast_str **nonce, const char *timestamp, const pjsi
 	RAII_VAR(char *, eid, ao2_global_obj_ref(entity_id), ao2_cleanup);
 	char hash[33];
 
+	/*
+	 * Note you may be tempted to think why not include the port. The reason
+	 * is that when using TCP the port can potentially differ from before.
+	 */
 	ast_str_append(&str, 0, "%s", timestamp);
 	ast_str_append(&str, 0, ":%s", rdata->pkt_info.src_name);
-	ast_str_append(&str, 0, ":%d", rdata->pkt_info.src_port);
 	ast_str_append(&str, 0, ":%s", eid);
 	ast_str_append(&str, 0, ":%s", realm);
 	ast_md5_hash(hash, ast_str_buffer(str));