Configuring Squid Proxy Server

Sure Squid server is a popular open source GPLd proxy and web cache. It has a variety of uses, from speeding up a web server by caching repeated requests, to caching web, name server query , and other network lookups for a group of people sharing network resources. It is primarily designed to run on Linux / Unix-like systems. Squid is a high-performance proxy caching server for Web clients, supporting FTP, gopher, and HTTP data objects. Unlike traditional caching software, Squid handles all requests in a single, non-blocking, I/O-driven process. Squid keeps meta data and especially hot objects cached in RAM, caches DNS lookups, supports non-blocking DNS lookups, and implements negative caching of failed requests. Squid consists of a main server program squid, a Domain Name System lookup program (dnsserver), a program for retrieving FTP data (ftpget), and some management and client tools.

1. Check the necessary RPM
#rpm –q squid

if it's not installed first install it

#yum install squid

2. Set the default gateway and the DNS on the proxy server, so it has a direct connection as an internet.
#system-config-network-tui

3. Give the information about your local network on the proxy server.
#nano /etc/squid/squid.conf
Press CTRL + W
Search – our_networks

4. Uncomment this lines
#acl our_networks src 192.168.1.0/24 192.168.2.0/24 //Remove # mark
#http_access allow our_networks //Remove # mark
5. Save (CTRL + O) and Exit (CTRL + X) file

6. Start the proxy service
#service squid start
#chkconfig squid on

Settings up proxy clients

The proxy client is an application that required internet through the proxy server
EX – Internet Explorer, Mozilla Firefox

Fire Fox
Edit --> Preferences --> Advanced --> Network --> Settings --> manually proxy configuration
http proxy : 192.168.2.101 port : 3128 // proxy server IP and port number

Now clients have to access internet through proxy………

Controlling web access through proxy

1. Open the following file
#nano /ect/squid/squid.conf
Press CTRL + W
Search – # http_access deny all

Put all the rules that you want to control web access through proxy under the above comment. All the block rules must come before the allow rules

• To block unwanted website
acl blockweb dstdomain .facebook.com .yahoo.com .google.com
http_access deny blockweb

• To block unwanted file download
acl blockfile urlpath_regex –i exe$ mp3$ avi$ rar$
http_access deny blockfile

• To allow POP3/ SMTP to access mail through proxy server
acl allowmail proto POP3 SMTP
http_access allow allowmail

2. Save (CTRL + O) and exit (CTRL +X) the file

3. Reload squid service
#service squid reload
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List of acl tags and examples
http://wiki.squid-cache.org
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