diff --git a/nping/NpingOps.cc b/nping/NpingOps.cc
index 67206804d..4ad2d27ce 100644
--- a/nping/NpingOps.cc
+++ b/nping/NpingOps.cc
@@ -146,7 +146,7 @@ NpingOps::NpingOps() {
     spoofsource=false;
     spoofsource_set=false;
 
-    bpf_filter_spec=0;
+    bpf_filter_spec=NULL;
     bpf_filter_spec_set=false;
 
     current_round=0;