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The Squid 2.5 Quick start Guide is
a concise information meant to step you through the basic installation and configuration
of Squid 2.5. This document is dedicated for beginners who want a simple Squid setup
running in Linux. For detailed configurations please refer our Configuration Manual
Step I - Downloading and compiling Squid You can download squid source file as a gzipped tar ball (squid-x.y-STABLE.tar.gz) available at http://www.squid-cache.org/ or from ftp://www.squid-cache.org/pub.
Next you have to extract the compressed archive file and change the working directory to squid tar -xvzf
squid-*-src.tar.gz
cd squid -* Now enter the following commands in order to configure, compile and install squid ./configure make make install This by
default, will install in "/usr/local/squid".
Type ./configure --help to view all available options. Step II - Basic Configuration Some basic
configurations are to be done. Uncomment and edit the following lines
in the configuration file found default at "/usr/local/squid/etc/squid.conf".
cache_dir this direcitve specifies the cache directory storage format and its size as given below. cache_dir ufs /usr/local/squid/cache 100 16 256 The value 100 denotes 100MB cache size. This can be adjusted to the required size. http_port Check http_port, 3128 is a default. http_access By default http_access is denied. The ACL rules should be modified to allow access only to the trusted clients. This is important because it prevents people from stealing your network resources. cache_effective_user & cache_effective_ group Set these directive to the user and group by which squid will run. This user should have the permission to read and write in the cache directory and to the log files. . Step III - Custom configuration based on your network needs For Configuring squid for proxy By default, squid is configured as a direct proxy . In order to cache web traffic with squid, the browser must be configured to use the squid proxy. This needs the following information
i. the proxy server's host name ii. the port by which the proxy server accepts connections. For Configuring squid for transparency Using
squid transparently is a two part process, requiring first that
squid be configured properly to accept non-proxy requests (performed in
the squid module) and second that web traffic gets redirected to the
squid port (achieved in three ways namely policy based routing, Using
smart switching or by setting squid Box as a gateway).
Getting transparent caching to work requires the following steps i. For some
operating systems, you have to configure and build a
version of Squid which can recognize the hijacked connections and
discern the destination addresses. For Linux this seems to work
automatically. For BSD-based systems, configure
squid with the --enable-ipf-transparent option and you have to
configure squid as
httpd_accel_host
virtual
httpd_accel_port 80 httpd_accel_with_proxy on httpd_accel_uses_host_header on ii. Next you have to configure your cache host to accept the redirected packets - any IP address, on port 80 - and deliver them to your cache application. This is typically done with IP filtering/forwarding features built into the kernel. In Linux they call this ipfilter (kernel 2.4.x), ipchains (2.2.x) or ipfwadm (2.0.x). For Configuring squid for Reverse Proxy To run Squid as
an accelerator, you probably want to listen on port 80.
And you have to define the machine you are accelerating for. This is
done in squid module,
http_port 80 httpd_accel_host visolve.com httpd_accel_port 81 httpd_accel_single_host on httpd_accel_with_proxy on If you are using Squid as an accelerator for a virtual host system, then instead of a 'hostname' here you have to use the word virtual as: http_port 80 httpd_accel_host virtual httpd_accel_port 81 httpd_accel_with_proxy on httpd_accel_single_host off Step IV - Starting Squid After you've
finished editing the configuration file, you can start
Squid for the first time. First, you must create the swap directories.
Do this by running Squid with the -z option:
/usr/local/squid/sbin/squid -z Once that completes, you can start Squid and try it out. Probably the best thing to do is run it from your terminal and watch the debugging output. Use this command: /usr/local/squid/sbin/squid -NCd1 If everything is working fine, then your console displays: "Ready to serve requests". If you want to run squid in the background, as a daemon process /usr/local/squid/sbin/squid You should be a privileged user to start/stop squid.. Step V - To check if Squid is working Check the cache.log file in your logs directory to find out if squid works correctly. This file contains the informational and error messages that Squid generates at runtime.
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