diff --git a/lib/sockunion.c b/lib/sockunion.c
index 75419b1..6a40f33 100644
--- a/lib/sockunion.c
+++ b/lib/sockunion.c
@@ -238,6 +238,7 @@
     {
       memset (&sin, 0, sizeof (struct sockaddr_in));
       sin.sin_family = AF_INET;
+      sin.sin_port = su->sin6.sin6_port;
       memcpy (&sin.sin_addr, ((char *)&su->sin6.sin6_addr) + 12, 4);
       memcpy (su, &sin, sizeof (struct sockaddr_in));
     }