diff --git a/source3/nmbd/nmbd_winsserver.c b/source3/nmbd/nmbd_winsserver.c
index 0a5b1c8..74af30f 100644
--- a/source3/nmbd/nmbd_winsserver.c
+++ b/source3/nmbd/nmbd_winsserver.c
@@ -1250,6 +1250,79 @@ to register name %s from IP %s.\n", nmb_namestr(question), inet_ntoa(p->ip) ));
 			 */
 
 			if(!find_ip_in_name_record(namerec, from_ip)) {
+				/*
+				 * Need to emulate the behaviour of Windows, as
+				 * described in:
+				 * http://lists.samba.org/archive/samba-technical/2001-October/016236.html
+				 * (is there an MS reference for this
+				 * somewhere?) because if the 1c list gets over
+				 * 86 entries, the reply packet is too big
+				 * (rdata>576 bytes) so no reply is sent.
+				 *
+				 * Keep only the "latest" 25 records, while
+				 * ensuring that the PDC (0x1b) is never removed
+				 * We do this by removing the first entry that
+				 * isn't the 1b entry for the same name,
+				 * on the grounds that insertion is at the end
+				 * of the list, so the oldest entries are at
+				 * the start.
+				 *
+				 */
+				while(namerec->data.num_ips>=25) {
+					struct name_record *name1brec = NULL;
+
+					DEBUG(3,("wins_process_name_registration_request: "
+						"More than 25 IPs already in "
+						"the list. Looking for a 1b "
+						"record\n"));
+
+					/* Use the same processing as a 1b name
+					 * query. */
+					wins_delete_all_tmp_in_memory_records();
+					fetch_all_active_wins_1b_names();
+
+					/* Per the above, find the 1b record, and then remove the first IP that isn't the same */
+					for(name1brec = subrec->namelist;
+							name1brec;
+							name1brec = name1brec->next ) {
+						if( WINS_STATE_ACTIVE(name1brec) &&
+								name1brec->name.name_type == 0x1b) {
+							DEBUG(3,("wins_process_name_registration_request: "
+								"Found the #1b record "
+								"with ip %s\n",
+								inet_ntoa(name1brec->data.ip[0])));
+							break;
+						}
+					}
+					if(!name1brec) {
+						DEBUG(3,("wins_process_name_registration_request: "
+							"Didn't find a #1b name record. "
+							"Removing the first available "
+							"entry %s\n",
+							inet_ntoa(namerec->data.ip[0])));
+						remove_ip_from_name_record(namerec, namerec->data.ip[0]);
+						wins_hook("delete", namerec, 0);
+					} else {
+						int i;
+						for(i=0; i<namerec->data.num_ips; i++) {
+							/* The name1brec should only have
+							 * the single IP address in it,
+							 * so we only check against the first one*/
+							if(!ip_equal_v4( namerec->data.ip[i], name1brec->data.ip[0])) {
+								/* The i'th entry isn't the 1b address; delete it  */
+								DEBUG(3,("wins_process_name_registration_request: "
+									"Entry at %d is not the #1b address. "
+									"About to remove it\n",
+									i));
+								remove_ip_from_name_record(namerec, namerec->data.ip[i]);
+								wins_hook("delete", namerec, 0);
+								break;
+							}
+						}
+					}
+				}
+				/* The list is guaranteed to be < 25 entries now
+				 * - safe to add a new one  */
 				add_ip_to_name_record(namerec, from_ip);
 				/* we need to update the record for replication */
 				get_global_id_and_update(&namerec->data.id, True);