diff --git a/doc/openwrt/iptables b/doc/openwrt/iptables
index 8671c22..aa86a61 100755
--- a/doc/openwrt/iptables
+++ b/doc/openwrt/iptables
@@ -12,6 +12,7 @@ start () {
     iptables -P OUTPUT ACCEPT
     iptables -P FORWARD ACCEPT
 
+    iptables -A INPUT -p udp --dport 53 -j ACCEPT
     iptables -A INPUT -p udp --dport 67 -j ACCEPT
     iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
     iptables -A INPUT -s 10.0.0.0/16 -j ACCEPT
diff --git a/mkpuzzles b/mkpuzzles
index 26e4d90..e18c87e 100755
--- a/mkpuzzles
+++ b/mkpuzzles
@@ -1,5 +1,7 @@
 #! /bin/sh -e
 
+set -e
+
 indir=$1; shift
 outdir=$1; shift
 
@@ -69,7 +71,7 @@ for dn in $indir/[0-9]*; do
 
     if [ -f $dn/Makefile ]; then
         # If there's a makefile, run make
-        make -C $dn DESTDIR=$(pwd)/$tgt
+        make -C $dn DESTDIR=$(pwd)/$tgt || exit 1
         files=$(cd $tgt; echo *)
     else
         # Otherwise, look for special files and copy the rest
@@ -94,7 +96,11 @@ for dn in $indir/[0-9]*; do
         done
     fi
 
-    # Append keys
+    # Append keys 
+    if ! [ -f $dn/key ]; then
+        echo "$dn/key: No such file or directory" 1>&2
+        exit 1
+    fi
     while read answer; do
         echo $points $answer
     done < $dn/key >> $uanswers
diff --git a/packages/crypto/190/key b/packages/crypto/190/key
new file mode 100644
index 0000000..6ab8796
--- /dev/null
+++ b/packages/crypto/190/key
@@ -0,0 +1 @@
+statistical information
diff --git a/packages/hackme/100/key b/packages/hackme/100/key
new file mode 100644
index 0000000..e69de29
diff --git a/packages/hackme/274/key b/packages/hackme/274/key
new file mode 100644
index 0000000..e69de29
diff --git a/packages/hackme/300/key b/packages/hackme/300/key
new file mode 100644
index 0000000..e69de29