squid proxy server installation and configuration RHEL7 / Centos7

squid proxy server is used to filter web traffic and reducing and fine tuning internet bandwidth.

Squid was originally developed as the Harvest object cache, part of the Harvest project at the University of Colorado Boulder. Further work on the program was completed at the University of California, San Diego and funded via two grants from the National Science Foundation. Duane Wessels forked the “last pre-commercial version of Harvest” and renamed it to Squid to avoid confusion with the commercial fork called Cached 2.0, which became NetCache. Squid version 1.0.0 was released in July 1996.

Squid is now developed almost exclusively through volunteer efforts.

Squid Proxy Server Profile

  • Packages : squid*
  • Service Name: squid
  • Default port : 3128
  • Config File : /etc/squid/squid.conf
  • Log file Path: /var/log/squid
  • Environment : RHEL 7, Centos 7 and RHEL 6

Installation process

[root@server ~]# yum install squid*
squid.x86_64 7:3.3.8-12.el7_0
Dependency Installed:
libecap.x86_64 0:0.2.0-8.el7 perl-Compress-Raw-Bzip2.x86_64 0:2.061-3.el7 perl-Compress-Raw-Zlib.x86_64 1:2.061-4.el7 perl-DBI.x86_64 0:1.627-4.el7 perl-Data-Dumper.x86_64 0:2.145-3.el7
perl-Digest.noarch 0:1.17-245.el7 perl-Digest-MD5.x86_64 0:2.52-3.el7 perl-IO-Compress.noarch 0:2.061-2.el7 perl-Net-Daemon.noarch 0:0.48-5.el7 perl-PlRPC.noarch 0:0.2020-14.el7

Enable and start the Service

[root@server ~]# systemctl enable squid
ln -s '/usr/lib/systemd/system/squid.service' '/etc/systemd/system/multi-user.target.wants/squid.service'
[root@server ~]# systemctl start squid
[root@server ~]# systemctl status squid
squid.service - Squid caching proxy
Loaded: loaded (/usr/lib/systemd/system/squid.service; enabled)
Active: active (running) since Sun 2016-04-17 13:47:33 IST; 34s ago
Process: 7989 ExecStart=/usr/sbin/squid $SQUID_OPTS -f $SQUID_CONF (code=exited, status=0/SUCCESS)
Process: 7983 ExecStartPre=/usr/libexec/squid/cache_swap.sh (code=exited, status=0/SUCCESS)
Main PID: 7999 (squid)
CGroup: /system.slice/squid.service
├─7999 /usr/sbin/squid -f /etc/squid/squid.conf
└─8001 (squid-1) -f /etc/squid/squid.conf
Apr 17 13:46:53 server.arkit.co.in squid[7989]: 2016/04/17 13:46:53| WARNING: Could not determine this machines public hostname. Please configure one or set 'visible_hostname'.
Apr 17 13:47:13 server.arkit.co.in squid[7989]: 2016/04/17 13:47:13| WARNING: Could not determine this machines public hostname. Please configure one or set 'visible_hostname'.
Apr 17 13:47:33 server.arkit.co.in squid[7989]: 2016/04/17 13:47:33| WARNING: Could not determine this machines public hostname. Please configure one or set 'visible_hostname'.
Apr 17 13:47:33 server.arkit.co.in squid[7999]: Squid Parent: will start 1 kids
Apr 17 13:47:33 server.arkit.co.in squid[7999]: Squid Parent: (squid-1) process 8001 started
Apr 17 13:47:33 server.arkit.co.in systemd[1]: Started Squid caching proxy.

Allow firewall port for squid

[root@server ~]# firewall-cmd --permanent --add-port=3128/tcp
[root@server ~]# firewall-cmd --reload

Default port of squid proxy is 3128 that’s why we have to allow port 3128.

Access Control List 

Open the configuration file and write the ACL as per requirement in ACL we can do so many things

  1. Restricting un-wanted (BAD) URL’s
  2. Restrict access to internet based on time period
  3. Control Downloads
  4. Restrict file type downloads
  5. Allow Networks to enable Internet access
  6. Download speed control
[root@server ~]# vim /etc/squid/squid.conf

To allow Network we have to write below ACL lines

acl localnet src 
http_access allow localnet

To allow ports using ACL

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
http_access deny !Safe_ports

Block bad sites

acl badsites url_regex "/etc/squid/badsites"
http_access deny badsites

write the bad sites in the file

[root@server ~]# cat /etc/squid/badsites

Block File downloads

acl blockfiles urlpath_regex "/etc/squid/blockfiles.acl"
http_access deny blockfiles

Block file type downloads, below is the example file to deny mp3, mp4, flv avi, 3gp, mpg and mpeg.

[root@server ~]# cat /etc/squid/blockfiles.acl

Time based access, which deny internet access from morning 10 Hours to 19 Hours

acl work_hours time 10:00-19:00 
http_access deny work_hours

restricting download speed ACL

acl speedcontrol src
delay_pools 1
delay_class 1 2
delay_parameters 1 524288/524288 52428/52428
delay_access 1 allow speedcontrol

Go to Client Side

Change the proxy address in your browser then try to access the website
IE Settings > Internet options > Connections > Lan Settings >


provide IP address and port number

Now see the logs watch the squid logs
/var/log/squid/ log file directory

The logs are a valuable source of information about Squid workloads and performance. The logs record not only access information, but also system configuration errors and resource consumption (eg, memory, disk space). There are several log file maintained by Squid. Some have to be explicitly activated during compile time, others can safely be deactivated during.

  • /var/log/squid/access.log : Most log file analysis program are based on the entries in access.log. You can use this file to find out who is using squid server and what they are doing etc
  • /var/log/squid/cache.log : The cache.log file contains the debug and error messages that Squid generates. If you start your Squid using the default RunCache script, or start it with the -s command line option, a copy of certain messages will go into your syslog facilities. It is a matter of personal preferences to use a separate file for the squid log data.
  • /var/log/squid/store.log : The store.log file covers the objects currently kept on disk or removed ones. As a kind of transaction log it is ususally used for debugging purposes. A definitive statement, whether an object resides on your disks is only possible after analysing the complete log file. The release (deletion) of an object may be logged at a later time than the swap out (save to disk).


You can use standard UNIX / Linux command such as grep / tail to view log files. You must login as root or sudo command to view log files.

Display log files in real time

Use tail command as follows:

~]# tail -f /var/log/squid/access.log
~]$ sudo tail -f /var/log/squid/access.log

Search log files
Use grep command as follows:

~]#grep 'string-to-search' /var/log/squid/access.log

That’s about squid proxy server installation and configuration

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26 Responses

  1. AKASH says:

    this topic is too good. if you write examples so it will be beneficial for us. thankyou

  2. afif sarker says:

    so usefull

  3. manoj says:

    yes this very much helpfull

  4. Carlitos says:

    I have problems in the configuration file ” /etc/squid/squid.conf ” when the line commented checklist
    ” Acl badsites url_regix ” / etc / squid / badsites ”
    ” Http_access deny badsites ” and create the path and add the addresses , and also add my network , I need help please when I restart the service will not start

  5. Carlitos says:

    Jul 18 21:19:48 defqon squid: Bungled /etc/squid/squid.conf line 27: acl badsite s url_regix “/etc/squid/badsite”
    Jul 18 21:19:48 defqon squid: 2016/07/18 21:19:48| WARNING: (B) ‘’ is a subnetwork of (A) ‘’
    Jul 18 21:19:48 defqon squid: 2016/07/18 21:19:48| WARNING: because of this ‘192 .168.0.0/24’ is ignored to keep splay tree searching predictable
    Jul 18 21:19:48 defqon squid: 2016/07/18 21:19:48| WARNING: You should probably remove ‘’ from the ACL named ‘localnet’
    Jul 18 21:19:48 defqon squid: 2016/07/18 21:19:48| FATAL: Invalid ACL type ‘url_ regix’
    Jul 18 21:19:48 defqon squid: FATAL: Bungled /etc/squid/squid.conf line 27: acl badsites url_regix “/etc/squid/badsite”
    Jul 18 21:19:48 defqon squid: Squid Cache (Version 3.3.8): Terminated abnormally .
    Jul 18 21:19:48 defqon squid: CPU Usage: 0.009 seconds = 0.005 user + 0.003 sys
    Jul 18 21:19:48 defqon squid: Maximum Resident Size: 24848 KB
    Jul 18 21:19:48 defqon squid: Page faults with physical i/o: 0
    Jul 18 21:19:48 defqon systemd: squid.service: control process exited, code=exit ed status=1
    Jul 18 21:19:48 defqon systemd: Failed to start Squid caching proxy.
    Jul 18 21:19:48 defqon systemd: Unit squid.service entered failed state.

    • Log itself is saying remove “”” WARNING: You should probably remove ‘’ from the ACL named ‘localnet’ “””
      please remove that rule from config and try

      • Carlitos says:

        Look this is the new error , I mentioned the lines of the error and start the service
        Jul 19 20:47:00 defqon squid: Bungled /etc/squid/squid.conf line 27: acl badsites url_regix “/etc/squid/badsite”
        Jul 19 20:48:24 defqon squid: Bungled /etc/squid/squid.conf line 40: http_access deny badsites

        By creating a file on the path “/ etc / squid / badsite ” is where the error occurs : /

  6. shashi kant says:

    hi can you please write a brief note on transparent proxy integrated with webmin and squid server

  7. jithin says:

    is there any way i can create new port and block some sites on that port? if possible please tell me how to set only one site for a port(i mean if i created a port for ex:5678 and give access to facebook.com only and deny for all other sites? means he/she only get facebook.com )

    • Yes That is possible, instead of 8080 or 3128 you can set whatever the port number you want. Port number should be Greater than 1000. Than write an rule saying that deny all URL except particular site.

      • jithin says:

        ok thanks also is it possible to create multiple ports? because i need to block sites for specific employee?for example if marketing dept need facebook.com and accounts dept dont eventually i need to create mutilple ports right? so is this possible in squid? please reply….

  8. @jithin, No need of creating multiple ports, we can restrict sites using proxy based on users and IP addresses. Example if finance dept IP series 192.168.2.x then restrict entire IP series by writing rule in proxy, If your marketing dept IP series 192.168.3.x then allow internet to that series. Or else create user authentication based on users we can restrict.

  9. chandu says:

    Nice article, very useful

  10. Suman Sen says:

    Mr. Ravi,
    This is Suman Sen from Bangladesh. The post is very good. But I am facing different problem. Please help me.
    My problem is like
    I have two different network, net1 and net2
    net1 can access facebook and youtube 13:00-14:00 and 15:00-16:00
    net2 can access facebook and youtube 12:00- 13:00 and 15:00-16:00

    what will be the solution, Please help

  11. two small spelling error in the # vim /etc/squid/squid.conf urlpath_regix & url_regix – > here is a spelling mistake -> write as a urlpath_regex and url_regex

  12. Sharad says:

    Hi Ravi…
    Great tutorial and easy to implement.
    But how can we authenticate users from LDAP using SSL(port 636).
    Is there any plugin or script for that.

  13. rinaz says:

    hi guyz please help me
    how to block access proxy by passing application but i tried with sonicwall nsa it is not success full

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