From the publisher website or publicity

ABOUT SIEGE
Siege is an http regression testing and benchmarking utility. It was designed to let web developers measure the performance of their code under duress, to see how it will stand up to load on the internet. Siege supports basic authentication, cookies, HTTP and HTTPS protocols. It allows the user hit a web server with a configurable number of concurrent simulated users. Those users place the webserver "under siege."

PLATFORM SUPPORT
Siege was written on GNU/Linux and has been successfully ported to AIX, BSD, HP-UX and Solaris. It should compile on most System V UNIX variants and on most newer BSD systems. Because Siege relies on POSIX.1b features not supported by Microsoft, it will not run on Windows. Of course you can use Siege to test a Windows HTTP server.

Keywords
AIX
basic authentication
benchmarking
BSD
cookies
GNU Linux
HP-Ux
http
http regression
HTTPS
internet testing
load testing
regression testing
Siege
Solaris
stress testing
V UNIX variants
web developers
web testing

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Vendor: Siege