How to configure transparent squid proxy server in centos 6.4

1 step 

squid installation
open terminal and type following command

#yum install squid  -y

2 step

now edit and change  main configuration file

#nano /etc/squid/squid.conf

# TRANSPARENT SQUID ON CENTOS 6.4

# 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

acl lan src 192.168.1.1/8   #******YOUR LOCAL LAN (NEW LINE)*****

# 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 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

#

# Recommended minimum Access Permission configuration:

#

# Only allow cachemgr access from localhost

http_access allow manager localhost

http_access deny manager

# 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

http_access allow lan  ############(ADD NEW LINE)#########

# Squid normally listens to port 3128

http_port 3128 transparent

# 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% 0f

refresh_pattern . 0 20% 4320

#visible_hostname localhost  #######ADD NEW LINE#######

step 3

 now, change firewall rule  

type command 

#iptables -I INPUT -s 192.168.8.14/8 -p tcp --dport 4480 -j ACCEPT

#iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j DNAT --to #192.168.8.14:4480

#iptables -t nat -A PREROUTING -i eth1 -p tcp --dport 80 -j REDIRECT --to-port 4480

#service iptables save

#service iptables restart

step 4

start squid service

command

#service squid restart

  

step5

 You can monitor the access log to see it working.
# tail -f /var/log/squid/access.log 

Step 6

Now install SquidGuard.
# yum install squidGuard

Step 7 
To do that you need to create a blacklists directory in the /var/squidGuard/ directory. Now, in the new blacklists directory use vim create and edit a text file named testdomains.
# cd /var/squidGuard
# mkdir blacklists
# cd blacklists
# vim testdomains
type in three lines of text to add some test-domains to block: yahoo.com
msn.com
whatever-you-want-to-block.com
save and exit.
Step 8
  Now edit the squidGuard.conf file to configure it to work with the testdomains file. You may want to back up the squidGuard.conf file before making changes.
# cp /etc/squid/squidGuard.conf /etc/squid/squidGuard.conf.BAK
# vim /etc/squid/squidGuard.conf
In the config file, add the following text elements in red. Be careful in your edits, incorrect syntax will cause squidGuard to fail. The beginning of the text file has been omitted.

#dest adult {
#   domainlist blacklists/porn/domains
#    urllist blacklists/porn/urls
#   expressionlist blacklists/porn/expressions
#   redirect        http://admin.foo.bar.de/cgi/blocked?clientaddr=%a+clientname=%n+clientuser=%i+clientgroup=%s+targetgroup=%t+url=%u #}

 dest test {
    domainlist testdomains
    redirect http://www.google.com
}
acl {
     admin {
     pass any
     }

     foo-clients within workhours {
     #   pass good !in-addr !adult any
     } else {
           pass any
     }

     bar-clients {
     pass local none
     }

     default {
            pass !test any
            rewrite dmz
            redirect http://www.google.com
     }
}
8. Now compile the SquidGuard blacklists and chown the blacklists to be accessible by Squid.
# squidGuard -b -d -C all
# chown -R squid /var/squidGuard/blacklists 
9. Edit the squid.conf file and then reload Squid.
# vim /etc/squid/squid.conf
add the following line to the squid.conf file around line 28:
url_rewrite_program /usr/bin/squidGuard
# service squid reload
or
# service squid restart
10. Now open the Firefox browser and test to see if your testdomains are successfully blocked, while every other domain is allowed.