Running Squid

Why Use Squid?

When you're at work, the machines you use may need to get access to the internet indirectly, via a firewall machine or an http proxy server (let's call this machine firewall_proxy_server). To save folks from having to go through the same trial and error with setting up Squid, I wrote up the following summary of the configuration for this scenario of using Squid to cache files downloaded via a firewall machine or http proxy server.

Configuring Squid

I found the following are the main settings needed to get Squid to listen for http requests on its default port 3128, and forward them to port 80 on the machine firewall_proxy_server, while keeping a cache of everything it retrieves in the directory /somewhere/with/space/squid_cache/ (configured with size 16384 megabytes), while allowing access from clients in the three subnets listed in the our_networks access control list:

Settings in configuration file /etc/sqlid/squid.conf

     cache_peer firewall_proxy_server parent 80 3130 default no-query
     cache_dir ufs    /somewhere/with/space/squid_cache 16384 16 256
     cache_access_log /somewhere/with/space/squid_cache/access.log
     cache_log        /somewhere/with/space/squid_cache/cache.log
     cache_store_log  /somewhere/with/space/squid_cache/store.log
     acl our_networks src 192.168.1.0/24 192.168.2.0/24 192.168.3.0/24
     http_access allow our_networks
     httpd_accel_host firewall_proxy_server
     httpd_accel_port 80
     httpd_accel_single_host on
     httpd_accel_with_proxy on

To get squid going initially, you need to first install the package:

     apt-get install squid

If it's not already done, to initialize the squid cache cache_dir you may need to run as root:

     squid -z

Then start squid using:

     invoke-rc.d squid start

To get squid to re-read its configuration file, use:

     squid -k reconfigure

You might need to do this for example if you want to change the settings while squid is running, e.g. to increase the size of the squid disk cache (cache_dir third parameter).

-- PeterKnaggs - 10 Dec 2004
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