diff --git a/nhrpd/nhrp_nhs.c b/nhrpd/nhrp_nhs.c
index b926a8d7b2..76c591fd79 100644
--- a/nhrpd/nhrp_nhs.c
+++ b/nhrpd/nhrp_nhs.c
@@ -189,7 +189,7 @@ static int nhrp_reg_send_req(struct thread *t)
 	hdr->flags |= htons(NHRP_FLAG_REGISTRATION_NAT);
 	ext = nhrp_ext_push(zb, hdr, NHRP_EXTENSION_NAT_ADDRESS);
 	cie = nhrp_cie_push(zb, NHRP_CODE_SUCCESS, &nifp->nbma, &if_ad->addr);
-	cie->prefix_length = 8 * sockunion_get_addrlen(&nifp->nbma);
+	cie->prefix_length = 8 * sockunion_get_addrlen(&if_ad->addr);
 	nhrp_ext_complete(zb, ext);
 
 	nhrp_packet_complete(zb, hdr);
diff --git a/nhrpd/nhrp_peer.c b/nhrpd/nhrp_peer.c
index 5f1e43a608..d9e8627a14 100644
--- a/nhrpd/nhrp_peer.c
+++ b/nhrpd/nhrp_peer.c
@@ -386,11 +386,12 @@ static void nhrp_handle_registration_request(struct nhrp_packet_parser *p)
 	struct nhrp_extension_header *ext;
 	struct nhrp_cache *c;
 	union sockunion cie_nbma, cie_proto, *proto_addr, *nbma_addr, *nbma_natoa;
-	int holdtime, natted = 0;
+	int holdtime, prefix_len, hostprefix_len, natted = 0;
 	size_t paylen;
 	void *pay;
 
 	debugf(NHRP_DEBUG_COMMON, "Parsing and replying to Registration Req");
+	hostprefix_len = 8 * sockunion_get_addrlen(&p->if_ad->addr);
 
 	if (!sockunion_same(&p->src_nbma, &p->peer->vc->remote.nbma))
 		natted = 1;
@@ -412,13 +413,17 @@ static void nhrp_handle_registration_request(struct nhrp_packet_parser *p)
 	zbuf_init(&payload, pay, paylen, paylen);
 
 	while ((cie = nhrp_cie_pull(&payload, hdr, &cie_nbma, &cie_proto)) != NULL) {
-		if (cie->prefix_length != 0xff && !(p->hdr->flags & htons(NHRP_FLAG_REGISTRATION_UNIQUE))) {
+		prefix_len = cie->prefix_length;
+		if (prefix_len == 0 || prefix_len >= hostprefix_len)
+			prefix_len = hostprefix_len;
+
+		if (prefix_len != hostprefix_len && !(p->hdr->flags & htons(NHRP_FLAG_REGISTRATION_UNIQUE))) {
 			cie->code = NHRP_CODE_BINDING_NON_UNIQUE;
 			continue;
 		}
 
 		/* We currently support only unique prefix registrations */
-		if (cie->prefix_length != 0xff) {
+		if (prefix_len != hostprefix_len) {
 			cie->code = NHRP_CODE_ADMINISTRATIVELY_PROHIBITED;
 			continue;
 		}
diff --git a/nhrpd/nhrp_shortcut.c b/nhrpd/nhrp_shortcut.c
index 4a6cbce31f..4faa9d7863 100644
--- a/nhrpd/nhrp_shortcut.c
+++ b/nhrpd/nhrp_shortcut.c
@@ -228,7 +228,7 @@ static void nhrp_shortcut_recv_resolution_rep(struct nhrp_reqid *reqid, void *ar
 	prefix.prefixlen = cie->prefix_length;
 
 	/* Sanity check prefix length */
-	if (prefix.prefixlen >= 8*prefix_blen(&prefix)) {
+	if (prefix.prefixlen >= 8*prefix_blen(&prefix) || prefix.prefixlen == 0) {
 		prefix.prefixlen = 8*prefix_blen(&prefix);
 	} else if (nhrp_route_address(NULL, &pp->dst_proto, &route_prefix, NULL) == NHRP_ROUTE_NBMA_NEXTHOP) {
 		if (prefix.prefixlen < route_prefix.prefixlen)