How to Install & Configure Squid Proxy Server in Centos 7

Squid Proxy Server is a popular proxy server that sits between client browser and your website and allows you to easily cache frequently requested web pages on your site. It improves website speed & performance. In this article, we will look at how to install & configure Squid Proxy Server in CentOS 7. You can also use these steps on Redhat & Fedora Linux systems.

How to Install & Configure Squid Proxy Server

Here are the steps to install & configure squid proxy server.

1. Update Software Repositories

Open terminal and run the following command to update CentOS software repositories.

$ sudo yum -y update

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2. Install Squid Package

Run the following command to install Squid Package.

$ yum -y install squid

If you see any prompts during installation, enter Y.

Once Squid server is installed, start it with the following command.

$ sudo systemctl start squid

If you want to automatically start squid at the time of boot, run the following command.

$ sudo systemctl enable squid

If you want to view the status of your squid server, run the following command

$ sudo systemctl status squid

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3. Configure Squid Proxy Server

Next, we will configure Squid Proxy Server. Open its configuration file found at /etc/squid/squid.conf using a text editor.

$ sudo vi /etc/squid/squid.conf

Look for the following line

http_port 3128

If you want to change the port to another number, replace 3128 with a port number of your choice. Also, set the proxy mode to transparent if you don’t want the Squid proxy server to change the requests & responses of your website.

http_port 3128 transparent

Please make sure that you have opened port 3128 on your firewall.

By default, Squid Proxy server is configured to block all incoming HTTP traffic using the following line.

http_access deny all

Change it to

http_access allow all

Restart Squid proxy to apply changes.

$ sudo systemctl restart squid

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4. Configure Squid Client

On your client machine, open your web browser (e.g. Firefox) and go to

Menu > Options > Network Settings > Settings

Select Manual proxy configuration in the displayed window. In the HTTP Proxy textbox, enter the IP address of machine that hosts your proxy server.

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At this point, you are good to use Squid Proxy. We have provided some optional configurations, in case you need them.

Create Access Control List (ACL)

If you are unable to access your proxy server from outside its network, then create an access control list. Open Squid Proxy configuration file

$ sudo vi /etc/squid/squid.conf

Add the following line to allow access from 54.43.32.21

acl localnet src 54.43.32.21

You can also allow access from an IP range using CIDR notations

acl localnet src 54.43.32.0/24

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Set up basic authentication

Squid also supports basic authentication. Run the following command to install httpd-tools

yum -y install httpd-tools

Once the installation is complete, create new file

$ sudo touch /etc/squid/passwd && chown squid /etc/squid/passwd

Use the following command to create password, replace user_name with your username

htpasswd /etc/squid/passwd user_name

Enter the password for this new user, when prompted.

Open Squid Proxy configuration file

$ sudo vi /etc/squid/squid.conf

Add the following lines.

auth_param basic program /usr/lib64/squid/basic_ncsa_auth /etc/squid/passwd
auth_param basic children 5
auth_param basic realm Squid Basic Authentication
auth_param basic credentialsttl 2 hours
acl auth_users proxy_auth REQUIRED
http_access allow auth_users

Restart Squid Proxy Server to apply changes.

$ sudo systemctl restart squid

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How to Block Websites using Squid Proxy

Squid proxy also allows you to block specific websites. Create a new file to list blocked websites

$ sudo vi /etc/squid/blocked.acl

Add the websites to be blocked, one per line. Each starting with a dot.

.twitter.com
.facebook.com
.pinterest.com

Open Squid configuration file

$ sudo vi /etc/squid/squid.conf

Add the following lines above your ACL list

acl blocked_websites dstdomain “/etc/squid/blocked.acl”
http_access deny blocked_websites

Save and close the file. Restart Squid Proxy to apply changes.

$ sudo systemctl restart squid

That’s it. Now your list of specified websites will be blocked.

In this article, we have looked at how to install and configure Squid Proxy server. We have also looked various additional configuration options.

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