siege  4.1.6
About: Siege is an http load testing and benchmarking utility.
  Fossies Dox: siege-4.1.6.tar.gz  ("unofficial" and yet experimental doxygen-generated source code documentation)  

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siege Documentation

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Siege is an open source regression test and benchmark utility. It can stress test a single URL with a user defined number of simulated users, or it can read many URLs into memory and stress them simultaneously. The program reports the total number of hits recorded, bytes transferred, response time, concurrency, and return status. Siege supports HTTP/1.0 and 1.1 protocols, the GET and POST directives, cookies, transaction logging, and basic authentication. Its features are configurable on a per user basis.

Most features are configurable with command line options which also include default values to minimize the complexity of the program's invocation. Siege allows you to stress a web server with n number of users t number of times, where n and t are defined by the user. It records the duration time of the test as well as the duration of each single transaction. It reports the number of transactions, elapsed time, bytes transferred, response time, transaction rate, concurrency and the number of times the server responded OK, that is status code 200.

Siege was designed and implemented by Jeffrey Fulmer in his position as Webmaster for Armstrong World Industries. It was modeled in part after Lincoln Stein's and it's data reporting is almost identical. But does not allow one to stress many URLs simultaneously; out of that need siege was born....

When a HTTP server is being hit by the program, it is said to be "under siege."


Siege was written for both web developers and web systems admin- istrators. It allows those individuals to test their programs and their systems under duress. As a web professional, you are responsible for the intregrity of your product, yet you have no control over who accesses it. Traffic spikes can occur at any moment. How do you know if you're prepared?

Siege will allow you to place those programs under duress, to allow you to better understand the load that they can with stand. You'll sleep better knowing your site can withstand the weight of 400 simultaneous transactions if your site currently peaks at 250.

A transaction is characterized by the server opening a socket for the client, handling a request, serving data over the wire and closing the socket upon completion. It is important to note that HUMAN internet users take time to digest the data which comes back to them. Siege users do not. In practice I've found that 400 simultaneous siege users translates to at least five times that amount in real internet sessions. This is why siege allows you to set a delay ( --delay=NUM ). When set, each siege user sleeps for a random number of seconds between 1 and NUM. Through your server logs you should be able to get the average amount of time spent on a page. It is recommended that you use that number for your delay when simulating internet activity.


The latest version of siege can be obtained via anonymous FTP:

The source repository is located on GitHub: git clone

You can view in your browser here:

Updates and announcements are distributed via JoeDog:


Siege was built with GNU autoconf. If you are familiar with GNU software, then you should be comfortable installing siege Please consult the file INSTALL for more details.


To enable HTTPS support, you must install both openssl and openssl-devel on your system.

To enable gzip transfer encoding, you will need both zlib and zlib-devel installed on your system.

All prerequisites must be installed at compile time. If you add the libraries after siege has been compiled, you will have to run ./configure, make and make install again.

Siege prereqs are not dependencies. If these libraries are not present, the application will still compile and function. It simply won't contain these functionalities.


Documentation is available in man pages siege(1) layingsiege(1) An html manual is included with this distribution: manual.html

Complete documentation for siege can be found at


Consult the file COPYING for complete license information.

Copyright (C) 2000-2023 by Jeffrey Fulmer

Permission is granted to anyone to make or distribute verbatim copies of this document as received, in any medium, provided that the copyright notice and this permission notice are preserved, thus giving the recipient permission to redistribute in turn.

Permission is granted to distribute modified versions of this document, or of portions of it, under the above conditions, provided also that they carry prominent notices stating who last changed them.

In addition, as a special exception, the copyright holders give permission to link the code of portions of this program with the OpenSSL library under certain conditions as described in each individual source file, and distribute linked combinations including the two.

You must obey the GNU General Public License in all respects for all of the code used other than OpenSSL. If you modify file(s) with this exception, you may extend this exception to your version of the file(s), but you are not obligated to do so.
If you do not wish to do so, delete this exception statement from your version. If you delete this exception statement from all source files in the program, then also delete it here.