How to Restrict the Access to Specific Web sites Using Squid Proxy Server on CentOS 6.2

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This howto covers the steps necessary to restrict the access to specific web sites using Squid Proxy cache server for CentOS 6.2. Before beginning this steps, please make sure you have properly configured the squid proxy server. If not, please follow this article to install squid proxy server on CentOS 6.2 (How to Install and Configure Squid Proxy Server on CentOS 6.2)

Squid has capability to read the containing lists of web sites or domains for use in ACLs. In this example, the setup always restricting access to ehowstuff.com network and Bad_Websites, but allow surfing during surfing_hours group’s only if the sites does not in Bad_Wesites (other that Bad_Websites). Follow this steps to implement restricting access to specific websites.

1. Open the squid.conf configuration file :

    [[email protected] ~]# vi /etc/squid/squid.conf
    

2. Create web folder under /etc/squid. This is to store any anonymous files such as Bad_Websites.squid.

    [[email protected] ~]# mkdir /etc/squid/web
    

3.Create Bad_Websites.squid and add the bad websites list.

    [[email protected] ~]# vi /etc/squid/web/Bad_Websites.squid
    

Example Bad website list :

    #List in /etc/squid/web/Bad_Websites.squid
    www.porn.com
    www.badwebsites.com
    

4. Define surfing_hour group’s name, surfing time and restricted websites file list.

    #Add this at the bottom of the ACL Section
    #
    acl surfing_hours time M T W H F 08:00-17:00
    acl Bad_Websites  dstdomain "/etc/squid/web/Bad_Websites.squid"
    #
    

5. Always restricting access to ehowstuff.com network and Bad_Wesites, but allow surfing during surfing_hours group’s only if the sites does not in Bad_Websites (other that Bad_Websites).

    # Only allow cachemgr access from ehowstuff.com
    http_access allow ehowstuff.com surfing_hours !Bad_Websites
    http_access deny Bad_Websites
    http_access deny ehowstuff.com
    

6. Restart Squid proxy server to take effect :

    [[email protected] ~]# service squid restart
    Stopping squid: ................                           [  OK  ]
    Starting squid: .                                          [  OK  ]
    

Full Configuration of the Squid Cache Proxy Configuration :

    #
    # Recommended minimum configuration:
    #
    acl manager proto cache_object
    acl localhost src 127.0.0.1/32 ::1
    acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1
    
    # Example rule allowing access from your local networks.
    # Adapt to list your (internal) IP networks from where browsing
    # should be allowed
    acl localnet src 10.0.0.0/8	# RFC1918 possible internal network
    acl localnet src 172.16.0.0/12	# RFC1918 possible internal network
    acl localnet src 192.168.0.0/16	# RFC1918 possible internal network
    acl localnet src fc00::/7       # RFC 4193 local private network range
    acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) machines
    acl ehowstuff.com src 192.168.1.0/24    # Your internal network
    
    acl SSL_ports port 443
    acl Safe_ports port 80		# http
    acl Safe_ports port 21		# ftp
    acl Safe_ports port 443		# https
    acl Safe_ports port 70		# gopher
    acl Safe_ports port 210		# wais
    acl Safe_ports port 1025-65535	# unregistered ports
    acl Safe_ports port 280		# http-mgmt
    acl Safe_ports port 488		# gss-http
    acl Safe_ports port 591		# filemaker
    acl Safe_ports port 777		# multiling http
    acl CONNECT method CONNECT
    
    #Add this at the bottom of the ACL Section
    #
    acl surfing_hours time M T W H F 08:00-17:00
    acl Bad_Websites  dstdomain "/etc/squid/web/Bad_Websites.squid"
    
    #
    # Recommended minimum Access Permission configuration:
    #
    # Only allow cachemgr access from localhost
    http_access allow manager localhost
    http_access deny manager
    
    # Only allow cachemgr access from ehowstuff.com
    http_access allow ehowstuff.com surfing_hours !Bad_Websites
    http_access deny Bad_Websites
    http_access deny ehowstuff.com
    
    
    
    # Deny requests to certain unsafe ports
    http_access deny !Safe_ports
    
    # Deny CONNECT to other than secure SSL ports
    http_access deny CONNECT !SSL_ports
    
    # We strongly recommend the following be uncommented to protect innocent
    # web applications running on the proxy server who think the only
    # one who can access services on "localhost" is a local user
    #http_access deny to_localhost
    
    #
    # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
    #
    
    # Example rule allowing access from your local networks.
    # Adapt localnet in the ACL section to list your (internal) IP networks
    # from where browsing should be allowed
    #http_access allow localnet
    http_access allow localhost
    
    # And finally deny all other access to this proxy
    http_access deny all
    
    # Squid normally listens to port 3128
    http_port 3128
    
    # We recommend you to use at least the following line.
    hierarchy_stoplist cgi-bin ?
    
    # Uncomment and adjust the following to add a disk cache directory.
    #cache_dir ufs /var/spool/squid 100 16 256
    
    # Leave coredumps in the first cache dir
    coredump_dir /var/spool/squid
    
    # Add any of your own refresh_pattern entries above these.
    refresh_pattern ^ftp:		1440	20%	10080
    refresh_pattern ^gopher:	1440	0%	1440
    refresh_pattern -i (/cgi-bin/|\?) 0	0%	0
    refresh_pattern .		0	20%	4320
    


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