diff --git a/snmpd-oid-daemon.sh b/snmpd-oid-daemon.sh
index 90f65f5..e172b10 100755
--- a/snmpd-oid-daemon.sh
+++ b/snmpd-oid-daemon.sh
@@ -529,8 +529,8 @@ function main() {
         break
       ;;
       *)
-        echo "invalid command '$cmd'" >&2
-        cmd=""
+        echo "invalid command '$cmd', exiting ..." >&2
+        break
       ;;
     esac
   done
diff --git a/test.sh b/test.sh
new file mode 100755
index 0000000..d029dc0
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,13 @@
+#!/bin/bash
+
+while :; do
+  echo -n P
+  sleep .$(($RANDOM % 3))
+  echo -n I
+  sleep .$(($RANDOM % 3))
+  echo -n "N"
+  sleep .$(($RANDOM % 3))
+  echo G
+  echo GET
+  echo .1.3.6.1.4.1.8072.9999.9999.4.2.0
+done