What is Snoopy?

Snoopy is a Win32 console app that lets you sniff TCP client-server protocols or connect to a TCP server and have an interactive (Telnet-like) session. It isn't a protocol analyzer like Ethereal nor is it Telnet. It is just a simple yet extremely handy tool to diagnose problems in your client-server protocol or to just snoop around.

Using Snoopy

Snoopy can run either as a proxy or as a client. As a proxy it can sit between a client and server and display the data flowing in between. As a client it can be used to connect to a server and issue commands against it.

Proxy Mode

Snoopy has two proxy modes — Tee and HTTP.

In Tee mode, Snoopy proxies requests between a client and a server without any knowledge of the underlying protocol. Tee mode can be used, for instance, to view traffic between a mail client and server or an IRC client and server.

In HTTP mode, Snoopy acts as an HTTP proxy. It is well suited to view browser traffic as it parses the HTTP request and connects to the requested HTTP server and port. It also handles SSL requests, but of course, SSL traffic isn't decrypted.

The image below shows Snoopy as an HTTP proxy listening on port 81 and a request for this site from the browser.

 

 

 

Client Mode

In client mode, Snoopy can connect to a TCP server and one can issue commands in an interactive session. For instance, to connect to an SMTP server (say, smtp.gmail.com) and issue a HELO command, you have Snoopy connect to the server on port 25 and type away.

 

 

 

In client mode, Snoopy can also use "script" files, which are basically files containing a list of commands to execute against the server as soon as Snoopy connects. This is handy to execute common test cases against a server.

 

Snoopy has a few others tricks it can do. To see more of what Snoopy can do, run Snoopy at the command line to see its usage.

Installing Snoopy

There is no install program for Snoopy. Snoopy is just a small console app, 61K in size. Simply save the Snoopy executable in some convenient location on your disk and run from there. It is best to run Snoopy from within a command shell (cmd, 4NT and the ilk).

 

Download Snoopy now.

 

Snoopy works on all flavors and versions of Windows, we think. If it doesn't work for you, let us know.

 

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