[Zope-Annce] ANNOUNCE: Pound - reverse proxy and load balancer - v1.9

Robert Segall roseg at apsis.ch
Wed Jun 1 11:25:29 EDT 2005

This is to announce the release of Pound v1.9.

Changes in this version:
- Added the VerifyList configuration flag (CA root certs + CRL)
- CRL checking code
- RewriteRedirect 2 - ignores port value for host matching
- Added -c flag (check-only mode)
- Added -v flag (verbose mode)
- Added -p flag for pid file name

Problems fixed:
- fixed a potential buffer overflow problem (in checking the Host
- added call to SSL_library_init
- added a check for MSIE before forcing SSL shutdown
- X-SSL-Cipher header is added only if HTTPSHeaders is non-zero
- added code for shorter linger on badly closed connections (IE
- fixed the locking for session checking (mutex_lock/unlock)

The software is at version 1.9 (production quality). Further testing 
(especially under heavy loads), improvements and suggestions are

What is Pound (from the Web page)

- a reverse-proxy: it passes requests from client browsers to one or
more back-end servers.
- a load balancer: it will distribute the requests from the client
browsers among several back-end servers, while keeping session
- an SSL wrapper: Pound will decrypt HTTPS requests from client browsers
and pass them as plain HTTP to the back-end browsers.
- an HTTP/HTTPS sanitizer: Pound will verify requests for correctness
and accept only well-formed ones.
- an HTTP/1.1 to 1.0 proxy.
- a fail-over-server: should a back-end server fail, Pound will take
note of the fact and stop passing requests to it until it recovers.
- a request redirector - it will pass client requests to separate groups
of servers, based on required URL and the presence or absence of headers
(pattern matching)

Pound was specifically developed to serve as a front-end for multiple 
instances of Zope running on top of a common ZEO storage, but can be
used with any other web server. A patch for the Python source of z2.py
is available as part of the distribution to allow using Pound's SSL

Pound is currently in use in several medium to large volume sites and
seems to be holding up quite well: largest reported site does about 5.5
million requests per day, peaking at over 450 requests per second. The
speed is well superior to other, equivalent solutions, the configuration
is much simpler and the necessary resources (CPU, RAM, disk) are much,
much lower.

Pound is distributed under the GPL.

For further information, download, etc. please see

Pound has its own mailing-list - just send a message to 
pound-subscribe at apsis.ch in order to join.

Enjoy and let me know how it works for you.
Robert Segall
Apsis GmbH
Postfach, Uetikon am See, CH-8707
Tel: +41-44-920 4904

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