diff --git a/proto/ospf/lsack.c b/proto/ospf/lsack.c
index 335ae1e1..f95caf52 100644
--- a/proto/ospf/lsack.c
+++ b/proto/ospf/lsack.c
@@ -22,7 +22,7 @@ ospf_lsack_direct_tx(struct ospf_neighbor *n,struct ospf_lsa_header *h)
   pk=(struct ospf_lsack_packet *)sk->tbuf;
   op=(struct ospf_packet *)sk->tbuf;
 
-  fill_ospf_pkt_hdr(n->ifa, pk, LSUPD);
+  fill_ospf_pkt_hdr(n->ifa, pk, LSACK);
 
   memcpy(pk+1,h,sizeof(struct ospf_lsa_header));
   len=sizeof(struct ospf_lsack_packet)+sizeof(struct ospf_lsa_header);
@@ -76,7 +76,7 @@ ospf_lsack_delay_tx(struct ospf_neighbor *n)
   pk=(struct ospf_lsack_packet *)sk->tbuf;
   op=(struct ospf_packet *)sk->tbuf;
 
-  fill_ospf_pkt_hdr(n->ifa, pk, LSUPD);
+  fill_ospf_pkt_hdr(n->ifa, pk, LSACK);
   h=(struct ospf_lsa_header *)(pk+1);
 
   while(!EMPTY_LIST(n->ackl))
@@ -115,7 +115,7 @@ ospf_lsack_delay_tx(struct ospf_neighbor *n)
 	}
 	*/
 
-	fill_ospf_pkt_hdr(n->ifa, pk, LSUPD);
+	fill_ospf_pkt_hdr(n->ifa, pk, LSACK);
 	i=0;
       }
     }