diff --git a/dlls/nsi/tests/nsi.c b/dlls/nsi/tests/nsi.c
index b6dd8f2416d..4cf49993ea1 100644
--- a/dlls/nsi/tests/nsi.c
+++ b/dlls/nsi/tests/nsi.c
@@ -842,7 +842,8 @@ static void test_tcp_stats( int family )
 
 static void test_tcp_tables( int family, int table_type )
 {
-    DWORD dyn_sizes[] = { FIELD_OFFSET(struct nsi_tcp_conn_dynamic, unk[2]), sizeof(struct nsi_tcp_conn_dynamic) };
+    DWORD dyn_sizes[] = { FIELD_OFFSET(struct nsi_tcp_conn_dynamic, unk[2]), FIELD_OFFSET(struct nsi_tcp_conn_dynamic, unk[3]),
+                          sizeof(struct nsi_tcp_conn_dynamic) };
     DWORD i, err, count, table_num, dyn_size, size;
     struct nsi_tcp_conn_key *keys;
     struct nsi_tcp_conn_dynamic *dyn_tbl, *dyn;
diff --git a/include/wine/nsi.h b/include/wine/nsi.h
index 0e20490e2a8..af35593b29c 100644
--- a/include/wine/nsi.h
+++ b/include/wine/nsi.h
@@ -334,7 +334,7 @@ struct nsi_tcp_conn_key
 struct nsi_tcp_conn_dynamic
 {
     UINT state;
-    UINT unk[3];
+    UINT unk[4];
 };
 
 struct nsi_tcp_conn_static