diff --git a/sys/netatalk/at_control.c b/sys/netatalk/at_control.c
index 42b547349db4..c1ce8a5f5431 100644
--- a/sys/netatalk/at_control.c
+++ b/sys/netatalk/at_control.c
@@ -429,7 +429,7 @@ at_ifinit(struct ifnet *ifp, struct at_ifaddr *aa, const struct sockaddr_at *sat
          * that phase 1 probes use only nodes, not net.node pairs.  Under
          * phase 2, both the net and node must be the same.
          */
-	AA_SAT(aa)->sat_len = sat->sat_len;
+	AA_SAT(aa)->sat_len = sizeof(struct sockaddr_at);
 	AA_SAT(aa)->sat_family = AF_APPLETALK;
 	if (ifp->if_flags & IFF_LOOPBACK) {
 		AA_SAT(aa)->sat_addr.s_net = sat->sat_addr.s_net;