Squid Web Proxy as ICAP Client
October 30, 2002
This package gives the necessary files to ICAP enable Squid Web Proxy
. It contains the following files:
For systems requirements, configuration guide and user manuals please
check out the Squid HomePage.This
version has only been tested on Redhat 7.1 Linux on i586.
A patch file over release 1.2 sources.
A gzipped tar file that will be extracted to /usr/local/squid containing
the Squid binaries for Redhat Linux 7.1 on i586
A sample configuration file squid.conf.sample
This README file.
A file describing the License to copy.
An earlier version of these sources are also available as a squid
ICAP client configuration page
Squid ICAP client project
What's New ?
Over release 1.2:
1. Support for processing OPTIONS header.
2. A new configuration option "icap_send_client_ip" to send IP
address of client in ICAP header as X-Client-IP .
3. Supports configurable preview size, with new config parameter, icap_preview_size.
4. The redundant configuration option icap_mode is removed, now.
5. Some bug fixes (default port number, host redirection
bug, header modification bug, small icap header size)
Over release 1.1:
1. Squid is now fully ICAP 1.0 compatible.
2. Support for both RESPMOD and REQMOD on a single request
3. Good configuration support using squid acl's . New
config parameters include icap_service, icap_class, icap_access, icap_mode
4. Chunked response from ICAP is supported if you set ICAP_CHUNKED
5. The ugly "-i" option is no more there!
6. A few bug fixes.
Over release 1.0 :
1. The icap config parameter name is changed from icap to "icap_mode"
2. The responses in respmod are sent in chunked form to the ICAP server
3. The ICAP client now sends a "Preview:" header for RESPMOD and waits
for a 100 Continue from the ICAP server before sending rest of "chunked"
4. The icap patch is upgraded to Squid HEAD. So, the binaries may have
developer bugs :-(
Over normal squid :
1. It is ICAP enabled. See file icap.c
2. New set of config parameters can be set in the configuration
file to reflect the mode of content modification
3. Enable ICAP support by configuring with "--enable-icap-support"
1. If you have a Linux Redhat 7.1 (or above) machine,
you can just extract the file isquid-bin.tgz under / . This
contains the pre-compiled binaries of icap enabled squid at /usr/local/squid
. Configure and run squid.
If you want to play with the sources or add new features to squid
or icap client please follow the remaining instructions,
2. Download ICAP enabled squid sources using one the following
(A) TARBALL: Download the gzipped tarball of
icap enabled squid sources from http://sourceforge.net/project/showfiles.php?group_id=47737
(B) SQUID DEVELOPERS: Patch the squid sources
with ICAP support:
(a) Download squid HEAD sources from http://www.squid-cache.org/Versions/v2/HEAD/
or use the one you already have.
(b) The patch file is available with the release. It is squid-HEAD-icap1.2.patch
(c) Goto the parent directory containing subdirectory squid and apply
patch -p4 < squid-HEAD-icap1.2.patch
(d) Alternatively, you can download the sources from the "icap" branch
from squid developer cvs repository at http://sf.net/cvs/?group_id=1781
. Please note that this may NOT be really up to date w.r.t icap support.
(C) SQUID_ICAP CLIENT DEVELOPERS: Check out
sources from squid-icap CVS repository using the 'stable' tag as
per the instructions at http://sf.net/cvs/?group_id=47737 using
cvs z3 -d:pserver:email@example.com:/cvsroot/icap-server
co -r stable squid-icap-client
and execute the script "bootstrap.sh" to create the configure
3. Configure and build squid sources with this patch.
You now have the squid installed
4. Please refer to http://www.squid-cache.org/Doc/FAQ/FAQ-2.html
other options to configure script and a detailed info on compiling squid
The complete configuration manual is available at http://squid.visolve.com/
. We just give you some quick reference here.
The config file for squid is /usr/local/squid/etc/squid.conf (assuming
your prefix was /usr/local/squid).
1. Note that the default port at which squid runs is 3128. If you want
to change it, change the line starting from http_port
2. If you are using an upstream proxy, you may want to set it using
the cache_peer parameter.
cache_peer proxy.india.hp.com parent 8088 default
3. You may also have to check whether the following lines show a valid
username and group.
4. Check that the access permissions are right! If you want to be liberal,
you can just have
http_access allow all
as the last line under http_access category.
5. Ensure that you have the write permissions to the log directory,
cache_dir and pid_filename
6. Configure the ICAP support using the instructions here
1. The first time you run squid, you need to create cache directories as
2. To run squid
3. To run squid in debug mode
squid -N -X
Now point your browser's proxy to the host running squid
at port 3128 (or whateever)
 The ICAP forum at http://www.i-cap.org/
 The OPES forum at http://www.ietf-opes.org/
 "Proxylet Local Execution Environment Local Binding", IETF
 IRML: A Rule Specification Language for Intermediary Services,
 Squid Web Proxy , http://www.squid-cache.org/
 Python Based ICAP Server, http://icap-server.sourceforge.net
 The Project Page, http://sf.net/projects/icap-server
 Squid ICAP client development page at Web Washer http://www.webwasher.com/squid-icap/
For any comments or feedback on this code , please feel free to write to:
($Id: squid.html,v 1.9 2003/12/08 04:47:46 geetham Exp $ )