Squid Proxy Server Configuration In Linux Centos Step By Step
How to Install Squid Proxy Server on CentOS 7 – phoenixNAP
Introduction
System administrators use the Squid Proxy to augment their content delivery. Squid Proxy specifically allows a server to cache frequently visited web pages.
How? When a user seeks a web page or file, the request goes to the proxy server — the intermediary device between the desktop computer and the internet. The proxy server pulls the resource and relays it to the user, by caching the new data and using it for future requests made to the same server.
In this guide, you will learn how to set up, configure, and install a Squid Proxy server on CentOS 7.
Prerequisites
CentOS operating systemAccess to a terminal window/command-line (Ctrl-Alt-T)A CentOS user with root or sudo privilegesThe yum package installer, included by defaultA text editor, such as vim
Steps for Installing Squid Proxy on CentOS
Step 1: Refresh CentOS Software Repositories
Ensure that you are working with the latest software version by updating your repositories.
Launch a terminal window, and enter the following:
sudo yum -y update
Step 2: Install Squid Package on CentOS
To install Squid, type:
yum -y install squid
Now start Squid by entering the following command:
systemctl start squid
To set up an automatic start at boot:
systemctl enable squid
Review the status of the service, use:
systemctl status squid
In the example below, we see that the state is ‘Active. ’
Configuring the Squid Proxy Server
The Squid configuration file is found at /etc/squid/
1. Open the file in your preferred text editor (vim was used in this example}:
sudo vi /etc/squid/
2. Navigate to find the _port option. Typically, this is set to listen on Port 3218. This port usually carries TCP traffic. If your system is configured for traffic on another port, change it here:
You may also set the proxy mode to transparent if you’d like to prevent Squid from modifying your requests and responses.
Change it as follows:
_port 1234 transparent
3. Navigate to the _acacess deny all option.
It is currently configured to block all HTTP traffic, and no web traffic is allowed as shown below.
Change this to the following:
_access allow all
4. Restart the Squid service by entering:
sudo systemctl restart squid
Configure Squid Client
The Squid proxy server is now configured. To configure the client server switch to your client machine and open your web browser.
If you’re using Firefox, you can find the proxy settings under:
Menu > Options > Network Settings > Settings
Select the radio button for Manual proxy configuration.
Use the IP address for the system hosting your Squid proxy.
To test, you can visit. Your IP address appears as the proxy server’s IP address.
Create an Access Control List (ACL)
For connections outside the proxy server’s local network, you need to configure the Access Control Lists (ACL). This may be necessary if you get a ‘refused to connect’ error.
To solve this problem, simply add to your list of safe ports with a new ACL entry.
Note: After each of the following steps, you should save and exit, then restart the Squid service to apply the new configuration.
Edit the /etc/squid/ file once again. Add a new line as follows:
acl localnet src 192. 166. 0. 10
This will create a rule that only allows the system at this IP address to connect.
Comment the line to identify the rule. Text after the # sign is ignored by Squid.
acl localnet src 192. 10 # test computer
You can specify a range of IP address as follows:
acl localnet src 192. 10/30
Open Squid Proxy Ports
To open a specific port, add the following:
acl Safe_ports port 123 # Custom port
To save changes, restart Squid:
systemctl restart squid
Set Up Proxy Authentication
Squid offers basic authentication alongside supporting other types of authentication.
First, install d-tools with the following command:
yum -y install d-tools
With the tool installed, create the new file:
touch /etc/squid/passwd && chown squid /etc/squid/passwd
To create the password, use this command:
htpasswd /etc/squid/passwd newuser
Exchange the ‘newuser‘ with your user name.
The system will prompt you to enter and confirm a password for ‘newuser. ’
Restart the proxy service and re-open your browser by inserting:
Edit the /etc/squid/ file, and add the following command 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
_access allow auth_users
From now on when you connect to the Linux proxy server, you will see a prompt for your username and password. Any unauthenticated person will be stopped by an error message.
How to Block Websites with Squid Proxy
1. Create and edit a new text file /etc/squid/ by entering:
2. In this file, add the websites to be blocked, starting with a dot:..
The dot specifies to block all subsites of the main site.
3. Open the /etc/squid/ file again:
4. Add the following lines just above your ACL list:
acl blocked_websites dstdomain “/etc/squid/”
_access deny blocked_websites
Conclusion
In this tutorial, you learned how to install, configure and secure a Squid HTTP Proxy server.
Squid improves processing time and streamlines bandwidth use quickly through its unique caching power. In its accelerator mode, your server can work with impressive speed. It significantly enhances your network’s performance, giving your system a competitive edge.
How to Create an HTTP Proxy Using Squid on CentOS 7/8
Web proxies have been around for quite some time now and have been used by millions of users around the globe. They have a wide range of purposes, most popular being online anonymity, but there are other ways you can take advantage of web proxies. Here are some ideas:
Online anonymity
Improve online security
Improve loading times
Block malicious traffic
Log your online activity
To circumvent regional restrictions
In some cases can reduce bandwidth usage
How Proxy Server Works
The proxy server is a computer that is used as an intermediary between the client and other servers from which the client may request resources. A simple example of this is when a client makes online requests (for example want to open a web page), he connects first to the proxy server.
The proxy server then checks its local disk cache and if the data can be found in there, it will return the data to the client, if not cached, it will make the request in the client’s behalf using the proxy IP address (different from the clients) and then return the data to the client. The proxy server will try to cache the new data and will use it for future requests made to the same server.
What is Squid Proxy
Squid is a web proxy that used my wide range of organizations. It is often used as a caching proxy and improving response times and reducing bandwidth usage.
For the purpose of this article, I will be installing Squid on a Linode CentOS 7 VPS and use it as an HTTP proxy server.
How to Install Squid on CentOS 7/8
Before we start, you should know that Squid, does not have any minimum requirements, but the amount of RAM usage may vary depending on the clients browsing the internet through the proxy server.
Squid is included in the base repository and thus the installation is simple and straightforward. Before installing it, however, make sure your packages are up to date by running.
# yum -y update
Proceed by installing squid, start and enable it on system startup using following commands.
# yum -y install squid
# systemctl start squid
# systemctl enable squid
At this point, your Squid web proxy should already be running and you can verify the status of the service with.
# systemctl status squid
Sample Output
● rvice – Squid caching proxy
Loaded: loaded (/usr/lib/systemd/system/rvice; enabled; vendor preset: disabled)
Active: active (running) since Thu 2018-09-20 10:07:23 UTC; 5min ago
Main PID: 2005 (squid)
CGroup: /
├─2005 /usr/sbin/squid -f /etc/squid/
├─2007 (squid-1) -f /etc/squid/
└─2008 (logfile-daemon) /var/log/squid/
Sep 20 10:07:23 tecmint systemd[1]: Starting Squid caching proxy…
Sep 20 10:07:23 tecmint squid[2005]: Squid Parent: will start 1 kids
Sep 20 10:07:23 tecmint squid[2005]: Squid Parent: (squid-1) process 2007 started
Sep 20 10:07:23 tecmint systemd[1]: Started Squid caching proxy.
Here are some important file locations you should be aware of:
Squid configuration file: /etc/squid/
Squid Access log: /var/log/squid/
Squid Cache log: /var/log/squid/
A minimum configuration file (without comments in it) looks like this:
acl localnet src 10. 0. 0/8 # RFC1918 possible internal network
acl localnet src 172. 16. 0/12 # RFC1918 possible internal network
acl localnet src 192. 168. 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 #
acl Safe_ports port 21 # ftp
acl Safe_ports port 443 #
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 # -mgmt
acl Safe_ports port 488 # gss-
acl Safe_ports port 591 # filemaker
acl Safe_ports port 777 # multiling
acl CONNECT method CONNECT
_access deny! Safe_ports
_access deny CONNECT! SSL_ports
_access allow localhost manager
_access deny manager
_access allow localnet
_access allow localhost
_access deny all
_port 3128
coredump_dir /var/spool/squid
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
Configuring Squid as an HTTP Proxy
Here, we will show you how to configure squid as an HTTP proxy using only the client IP address for authentication.
Add Squid ACLs
If you wish to allow the IP address to access the web through your new proxy server, you will need to add a new ACL (access control list) line in the configuration file.
# vim /etc/squid/
The line you should add is:
acl localnet src
Where is the actual client IP address you wish to add. The line should be added at the beginning of the file where the ACLs are defined. It is a good practice to add a comment next to ACL which will describe who uses this IP address.
It is important to note that if Squid is located outside your local network, you should add the public IP address of the client.
You will need to restart Squid so the new changes can take effect.
# systemctl restart squid
Open Squid Proxy Ports
As you may have seen in the configuration file, only certain ports are allowed for connecting. You can add more by editing the configuration file.
acl Safe_ports port XXX
Where XXX is the actual port you wish to load. Again it is a good idea to leave a comment next to that will describe what the port is going to be used for.
For the changes to take effect, you will need to restart squid once more.
Squid Proxy Client Authentication
You will most probably want your users to authenticate before using the proxy. For that purpose, you can enable basic HTTP authentication. It is easy and fast to configure.
First, you will need d-tools installed.
# yum -y install d-tools
Now let’s create a file that will later store the username for the authentication. Squid runs with user “squid” so the file should be owned by that user.
# touch /etc/squid/passwd
# chown squid: /etc/squid/passwd
Now we will create a new user called “proxyclient” and setup its password.
# htpasswd /etc/squid/passwd proxyclient
New password:
Re-type new password:
Adding password for user proxyclient
Now to configure the authentication open the configuration file.
After the ports ACLs 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
_access allow auth_users
Save the file and restart squid so that the new changes can take effect:
Block Websites on Squid Proxy
Finally, we will create one last ACL that will help us block unwanted websites. First, create the file that will store the blacklisted sites.
# touch /etc/squid/
You can add some domains you wish to block. For example:..
The proceeding dot tells squid to block all references to that sites including dsite1,, etc.
Now open Squid’s configuration file.
Just after the ports ACLs add the following two lines:
acl bad_urls dstdomain “/etc/squid/”
_access deny bad_urls
Now save the file and restart squid:
Once everything configured correctly, now you can configure your local client browser or operating system’s network settings to use your squid HTTP proxy.
Conclusion
In this tutorial, you learned how to install, secure and configure a Squid HTTP Proxy server on your own. With the information you just got, you can now add some basic filtering for incoming and outgoing traffic through Squid.
If you wish to go the extra mile, you can even configure squid to block some websites during working hours to prevent distractions. If you have any questions or comments, please post them in the comment section below.
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How to Install Squid Proxy Server on CentOS 7 – phoenixNAP
Introduction
System administrators use the Squid Proxy to augment their content delivery. Squid Proxy specifically allows a server to cache frequently visited web pages.
How? When a user seeks a web page or file, the request goes to the proxy server — the intermediary device between the desktop computer and the internet. The proxy server pulls the resource and relays it to the user, by caching the new data and using it for future requests made to the same server.
In this guide, you will learn how to set up, configure, and install a Squid Proxy server on CentOS 7.
Prerequisites
CentOS operating systemAccess to a terminal window/command-line (Ctrl-Alt-T)A CentOS user with root or sudo privilegesThe yum package installer, included by defaultA text editor, such as vim
Steps for Installing Squid Proxy on CentOS
Step 1: Refresh CentOS Software Repositories
Ensure that you are working with the latest software version by updating your repositories.
Launch a terminal window, and enter the following:
sudo yum -y update
Step 2: Install Squid Package on CentOS
To install Squid, type:
yum -y install squid
Now start Squid by entering the following command:
systemctl start squid
To set up an automatic start at boot:
systemctl enable squid
Review the status of the service, use:
systemctl status squid
In the example below, we see that the state is ‘Active. ’
Configuring the Squid Proxy Server
The Squid configuration file is found at /etc/squid/
1. Open the file in your preferred text editor (vim was used in this example}:
sudo vi /etc/squid/
2. Navigate to find the _port option. Typically, this is set to listen on Port 3218. This port usually carries TCP traffic. If your system is configured for traffic on another port, change it here:
You may also set the proxy mode to transparent if you’d like to prevent Squid from modifying your requests and responses.
Change it as follows:
_port 1234 transparent
3. Navigate to the _acacess deny all option.
It is currently configured to block all HTTP traffic, and no web traffic is allowed as shown below.
Change this to the following:
_access allow all
4. Restart the Squid service by entering:
sudo systemctl restart squid
Configure Squid Client
The Squid proxy server is now configured. To configure the client server switch to your client machine and open your web browser.
If you’re using Firefox, you can find the proxy settings under:
Menu > Options > Network Settings > Settings
Select the radio button for Manual proxy configuration.
Use the IP address for the system hosting your Squid proxy.
To test, you can visit. Your IP address appears as the proxy server’s IP address.
Create an Access Control List (ACL)
For connections outside the proxy server’s local network, you need to configure the Access Control Lists (ACL). This may be necessary if you get a ‘refused to connect’ error.
To solve this problem, simply add to your list of safe ports with a new ACL entry.
Note: After each of the following steps, you should save and exit, then restart the Squid service to apply the new configuration.
Edit the /etc/squid/ file once again. Add a new line as follows:
acl localnet src 192. 166. 0. 10
This will create a rule that only allows the system at this IP address to connect.
Comment the line to identify the rule. Text after the # sign is ignored by Squid.
acl localnet src 192. 10 # test computer
You can specify a range of IP address as follows:
acl localnet src 192. 10/30
Open Squid Proxy Ports
To open a specific port, add the following:
acl Safe_ports port 123 # Custom port
To save changes, restart Squid:
systemctl restart squid
Set Up Proxy Authentication
Squid offers basic authentication alongside supporting other types of authentication.
First, install d-tools with the following command:
yum -y install d-tools
With the tool installed, create the new file:
touch /etc/squid/passwd && chown squid /etc/squid/passwd
To create the password, use this command:
htpasswd /etc/squid/passwd newuser
Exchange the ‘newuser‘ with your user name.
The system will prompt you to enter and confirm a password for ‘newuser. ’
Restart the proxy service and re-open your browser by inserting:
Edit the /etc/squid/ file, and add the following command 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
_access allow auth_users
From now on when you connect to the Linux proxy server, you will see a prompt for your username and password. Any unauthenticated person will be stopped by an error message.
How to Block Websites with Squid Proxy
1. Create and edit a new text file /etc/squid/ by entering:
2. In this file, add the websites to be blocked, starting with a dot:..
The dot specifies to block all subsites of the main site.
3. Open the /etc/squid/ file again:
4. Add the following lines just above your ACL list:
acl blocked_websites dstdomain “/etc/squid/”
_access deny blocked_websites
Conclusion
In this tutorial, you learned how to install, configure and secure a Squid HTTP Proxy server.
Squid improves processing time and streamlines bandwidth use quickly through its unique caching power. In its accelerator mode, your server can work with impressive speed. It significantly enhances your network’s performance, giving your system a competitive edge.
Frequently Asked Questions about squid proxy server configuration in linux centos step by step
How do I install and configure Squid proxy on CentOS 7?
How to Install Squid Proxy Server on CentOS 7Steps for Installing Squid Proxy on CentOS. Step 1: Refresh CentOS Software Repositories. Step 2: Install Squid Package on CentOS.Configuring the Squid Proxy Server. Configure Squid Client. Create an Access Control List (ACL) Open Squid Proxy Ports. Set Up Proxy Authentication.Jul 26, 2019
How do I install and configure Squid proxy on CentOS 8?
To install Squid on a CentOS 8/RHEL 8 server, proceed by following these steps.Step 1: Update your server. … Step 2: Install Squid. … Step 3: Configure forward proxy settings. … Step 4: Start Squid and allow its service on your firewall. … Step 5: Configure CentOS client.Feb 28, 2020
How install and configure Squid proxy on CentOS 6 step by step?
How To Install Squid Proxy on CentOS 6Step 1 – Spin up a CentOS 6.3 x64 droplet.Step 2 – Install Squid. … Step 3 – Setup Access Restrictions. … Step 4 – Configure Squid Proxy. … Step 5 – Start Squid proxy service. … Step 6 – Modify your browser’s proxy settings. … Step 7 – Verify Squid proxy works.Apr 4, 2013
