--- common/argus_filter.c
+++ common/argus_filter.c
@@ -4261,6 +4261,7 @@
    protoid[0] = 0;
    protoid[1] = 0;
    protoid[2] = 0;
+   protoid[4] = 0;
 
    for (i = 0; i < ARGUS_MAXEPROTODB; i++) {
       if ((p = argus_eproto_db[i]) != NULL) {