How to Restrict Web Access By Time Using Squid Proxy Server on CentOS 6.2

This howto covers the steps necessary to control internet access by time 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)
1. Open the squid.conf configuration file :

[root@centos62 ~]# vi /etc/squid/squid.conf

2. In this example, the setup just allow surfing_hour’s access from the howtolinux247.info network, while always restricting access to howtolinux247.info network other than surfing hour.

# Example rule allowing access from your local networks.
# Adapt to list your (internal) IP networks from where browsing
# should be allowed
acl howtolinux247.info src 192.168.1.0/24    # Your howtolinux247.info internal network

3. Define surfing_hour group’s name and time.

#Add this at the bottom of the ACL Section
#
acl surfing_hours time M T W H F 08:00-17:00
#

4. Always restricting access to howtolinux247.info, but allow during surfing hours only.

# Only allow cachemgr access from howtolinux247.info
http_access allow howtolinux247.info surfing_hours
http_access deny howtolinux247.info

5. Restart Squid proxy server to take effect :

[root@centos62 ~]# 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 howtolinux247.info src 192.168.1.0/24    # Your howtolinux247.info 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
#
# 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 howtolinux247.info
http_access allow howtolinux247.info surfing_hours
http_access deny howtolinux247.info



# 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
http_access allow howtolinux247.info

# 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