diff --git a/config/plugin/network_problem.sh b/config/plugin/network_problem.sh
index 645a84b0..51be5137 100755
--- a/config/plugin/network_problem.sh
+++ b/config/plugin/network_problem.sh
@@ -3,13 +3,21 @@
 # This plugin checks for common network issues. Currently, it only checks
 # if the conntrack table is full. 
 
+OK=0
+NONOK=1
+UNKNOWN=2
+
+[ -f /proc/sys/net/ipv4/netfilter/ip_conntrack_max ] || echo $UNKNOWN
+[ -f /proc/sys/net/ipv4/netfilter/ip_conntrack_count ] || echo $UNKNOWN
+
 conntrack_max=$(cat /proc/sys/net/ipv4/netfilter/ip_conntrack_max)
 conntrack_count=$(cat /proc/sys/net/ipv4/netfilter/ip_conntrack_count)
+
 if (( conntrack_count >= conntrack_max )); then
   echo "Conntrack table full"
-  exit 1
+  exit $NONOK
 fi
 
 echo "Conntrack table available"
-exit 0
+exit $OK