Find Squid Proxy Server
Proxy Servers – Squid | Ubuntu
Squid is a full-featured web proxy cache server application which provides proxy and cache services for Hyper Text Transport Protocol (HTTP), File Transfer Protocol (FTP), and other popular network protocols. Squid can implement caching and proxying of Secure Sockets Layer (SSL) requests and caching of Domain Name Server (DNS) lookups, and perform transparent caching. Squid also supports a wide variety of caching protocols, such as Internet Cache Protocol (ICP), the Hyper Text Caching Protocol (HTCP), the Cache Array Routing Protocol (CARP), and the Web Cache Coordination Protocol (WCCP).
The Squid proxy cache server is an excellent solution to a variety of proxy and caching server needs, and scales from the branch office to enterprise level networks while providing extensive, granular access control mechanisms, and monitoring of critical parameters via the Simple Network Management Protocol (SNMP). When selecting a computer system for use as a dedicated Squid caching proxy server for many users ensure it is configured with a large amount of physical memory as Squid maintains an in-memory cache for increased performance.
Installation
At a terminal prompt, enter the following command to install the Squid server:
sudo apt install squid
Configuration
Squid is configured by editing the directives contained within the /etc/squid/ configuration file. The following examples illustrate some of the directives which may be modified to affect the behavior of the Squid server. For more in-depth configuration of Squid, see the References section.
Tip
Prior to editing the configuration file, you should make a copy of the original file and protect it from writing so you will have the original settings as a reference, and to re-use as necessary. Make this copy and protect it from writing using the following commands:
sudo cp /etc/squid/ /etc/squid/
sudo chmod a-w /etc/squid/
To set your Squid server to listen on TCP port 8888 instead of the default TCP port 3128, change the _port directive as such:
_port 8888
Change the visible_hostname directive in order to give the Squid server a specific hostname. This hostname does not necessarily need to be the computer’s hostname. In this example it is set to weezie
visible_hostname weezie
The cache_dir option allows one to configure an on-disk cache, the default option is on-memory cache. The cache_dir directive takes the following arguments:
cache_dir
In the config file you can find the default cache_dir directive commented out:
# Uncomment and adjust the following to add a disk cache directory.
#cache_dir ufs /var/spool/squid 100 16 256
You can just use the default option but you can also customize your cache directory, basically changing the
ufs: the old well-known Squid storage format that has always been there.
aufs: uses the same storage format as ufs, utilizing POSIX-threads to avoid blocking the main Squid process on disk-I/O. This was formerly known in Squid as async-io.
diskd: uses the same storage format as ufs, utilizing a separate process to avoid blocking the main Squid process on disk-I/O.
rock: is a database-style storage. All cached entries are stored in a “database” file, using fixed-size slots. A single entry occupies one or more slots.
If you want to use a different directory type please take a look at their different options.
Using Squid’s access control, you may configure use of Internet services proxied by Squid to be available only users with certain Internet Protocol (IP) addresses. For example, we will illustrate access by users of the 192. 168. 42. 0/24 subnetwork only:
Add the following to the bottom of the ACL section of your /etc/squid/ file:
acl fortytwo_network src 192. 0/24
Then, add the following to the top of the _access section of your /etc/squid/ file:
_access allow fortytwo_network
Using the excellent access control features of Squid, you may configure use of Internet services proxied by Squid to be available only during normal business hours. For example, we’ll illustrate access by employees of a business which is operating between 9:00AM and 5:00PM, Monday through Friday, and which uses the 10. 1. 0/24 subnetwork:
acl biz_network src 10. 0/24
acl biz_hours time M T W T F 9:00-17:00
_access allow biz_network biz_hours
Note
After making changes to the /etc/squid/ file, save the file and restart the squid server application to effect the changes using the following command entered at a terminal prompt:
sudo systemctl restart rvice
If formerly a customized squid3 was used that set up the spool at /var/log/squid3 to be a mountpoint, but otherwise kept the default configuration the upgrade will fail. The upgrade tries to rename/move files as needed, but it can’t do so for an active mountpoint. In that case please either adapt the mountpoint or the config in /etc/squid/ so that they match.
The same applies if the include config statement was used to pull in more files from the old path at /etc/squid3/. In those cases you should move and adapt your configuration accordingly.
References
Squid Website
Ubuntu Wiki Squid page.
How To Setup and Configure a Proxy Server – Squid Proxy
A proxy server has many use cases. it could range from personal internet access to restrict organization systems/servers to access the external world or to limit external internet access for a set of servers on the cloud.
The best way to configure a proxy server is by using the Squid proxy. It is a widely used proxy server.
In this article, we have covered the following.
Install proxy serverConfigure the proxy serverConfigure basic proxy authentication.
Note: This tutorial is tested on CentOS 7. For Ubuntu setup, check this tutorial – Squid Proxy Setup On Ubuntu
Install Proxy Server: Squid Proxy
Step1: Update the server
sudo yum update -y
Step 2: Configure EPEL repo.
sudo yum -y install epel-release
sudo yum -y update
sudo yum clean all
Step 3: Install squid
sudo yum -y install squid
Step 4: Start and enable squid server.
sudo systemctl start squid
sudo systemctl enable squid
Step 5: Check the status of squid server.
sudo systemctl status squid
Configure Proxy Server: Squid Proxy
All the configurations for the squid server are present in /etc/squid/ file.
Configure proxy Sources To Access Internet
First, you need to configure the sources from which squid proxy should accept connections. For example, you might need to access this proxy server only from your home network or from specific CIDR ranges.
You can add a source IP range with an ACL using the following format.
acl localnet src 110. 220. 330. 0/24
Open /etc/squid/nffile and add the source add as shown below. Change the IP to the desired network/IP source based on your needs. In the following example, we have added a single source IP.
Restart the proxy server after making the ACL changes.
sudo systemctl restart squid
Test proxy Server Connectivity
Test if the proxy server is working using a simple curl request. Use the following curl format. By default squid proxy runs on 3128 port.
curl -x
Configure Proxy Authentication
Along with access ACL’s, you can add basic authentication to your proxy server for extra security. Follow the steps given below for setting up a basic auth for the squid proxy server.
Step 1: Install d-tools
sudo yum -y install d-tools
Step 2: Create a passwd file and make squid as the file owner.
sudo touch /etc/squid/passwd && sudo chown squid /etc/squid/passwd
Step 3: Add pxuser to the password file using htpasswd utility. It will prompt for a custom password. Enter a strong password you need. This username and password will be used for all connections through this proxy.
sudo htpasswd /etc/squid/passwd pxuser
Step 4: Open squid config file.
sudo vi /etc/squid/
Add the following to the config file and save it.
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
Step 5: Now, restart squid server for the configuration changes to take place.
Step 6: Now if you test the proxy connection using curl, you will get the “authentication required message” as shown below.
Now, test the connectivity with proxy user and password we configured in step 3. An example syntax is shown below.
curl -x –proxy-user pxuser:12345 -I With username and password, your proxy request should go through.
Blocking Websites
Another great use of the proxy server is restricting the website access. Follow the steps below for creating a block list.
Step 1: Open a blocked list file.
sudo vi /etc/squid/blocked_sites
Add the websites to be blocked in the file. For example,
Step 2: Open the squid config file.
Add the following to the ACL list.
acl blocked_sites dstdomain “/etc/squid/blocked_sites”
_access deny blocked_sites
Step 3: Restart the squid server.
Now if you try to access the blocked site through the proxy, you will get a forbidden message as shown below.
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Ways to setup Squid proxy server and helpful tips | AT&T Cybersecurity
This blog was written by an independent guest blogger.
A squid proxy server has two major functions. First, it is an intermediary proxy. Second, it provides cache services for popular network protocols including HTTP and FTP. The use of proxies and cache services makes up a better internet user experience.
Proxies provide added layers of security and cache services that make loading processes faster. Obviously, getting both services from a single provider is highly efficient.
What is a Squid proxy server?
Squid is a Unix-based proxy server that can do both caching and proxying. It can cache any web content to the user or requestor that is from a closer data storage point. It frequently caches large media files and web pages to reduce bandwidth congestion. Thus it decreases loading periods.
Squid supports several caching protocols, such as hypertext caching protocols (HTCP), internet cache protocol (ICP), cache array routing protocol (CARP), and web cache communication protocol (WCCP). It also processes caching requests from Domain Name Server (DNS) lookups and Secure Sockets Layer (SSL).
You wouldn’t want to miss enjoying the benefits of Squid proxy servers. Here are some ways to set the server up along with tips to maximize your use out of it.
Ways to setup a Squid proxy server
Squid proxy servers are usually installed in a separate server from the servers with the original content.
The first thing to do is to update your server to install the squid proxy server. Check if the server is running by checking its status in the code, before starting to configure the system.
Adding allowable sites
In the configuration process, you sift through the sites that are allowable through the intermediary web proxy. These sites are considered as part of your ACL or access control list. These are the only sites that the Squid server will proxy and cache data for.
Go through the list of acceptable websites and input in the code. Once all of these are encoded in, restart the proxy and check the status afterward.
It’s safe to include an open port in the control list. The open port acts as the passageway for the other sites that were not defined and placed under the list.
Blocking websites
As much as you can configure the server to include sites to process, you can also block access to several websites.
In order to carry out this requirement, create a folder under the access command list that will hold all the restricted sites. Limiting internet access is one of the prominent uses of proxy servers, in general.
After listing the blocked or restricted sites, a prompt will appear in the code. Aside from blocked sites, you can also create a list of blocked keywords. Many companies configure their proxies to block access to several social networking sites, such as Facebook, Twitter, and Instagram.
Once the list is finalized, make sure to save the file and restart the proxy to confirm.
Configuring additional authentication
To install an added layer of protection in your Squid proxy, install d-tools. This lets you create a password for the proxy. Make sure to assign the proxy server as the file owners. Otherwise, your access will be restricted as well.
You can also add a pxuser using htpasswd utility. This calls for a different and much stronger password. Make sure not to forget this username and password. This will be used to authorize all proxy connections later on.
Helpful tips to note
First of all, every time you change or configure the components of the proxy server, make a copy of the original file. Much like editing an article or creating digital art, it’s important to have layers or to keep the previous copies to note the differences.
In this manner, if something goes wrong after the attempted configuration, you can easily pull out and use the previous code. Aside from that, you can also do some troubleshooting by comparing the old and new code. It’s easy to point out the differences or the mistakes done in the newer version.
You need to input a command to keep the original file before configuration.
The next tip is to remember to constantly rotate the log files. Rotating large files leads to better proxy performance.
Also, always be careful in labeling your ACL. A proxy will not process or allow any domain that shares a name with another. This measure, however demanding it may seem, provides an added layer of protection. More than that, it supports the Squid proxy in carrying out one of its main tasks.
Another tip that helps improve the loading time of content is that you can configure the Squid proxy server to limit the downloadable file size. The configuration must state the maximum allowable size. Any file larger than that will not be processed by the server. The limit is applicable to all users and all file types. However, the limit can also be specified per user.
This method of limiting the downloadable size is a common practice in office set-ups that share servers. It is one way of decongesting the bandwidth and increasing the performance of the server for all users.
In the same manner, the proxy server can also limit the maximum size for uploading files.
Since caching is one of the main tasks of Squid proxies, it is designed to automatically cache the data of the websites under the ACL. But if some of the sites under the list do not need caching, you can exempt them from the process. You can pinpoint the websites to not cache their data regularly.
All you need to do is create a file under the access list and label it as no_cache domain. Once set, configure and restart the system.
Conclusion
The use of web proxies is getting more prevalent as more users are discovering its benefits. From added online security to a better internet experience, proxies are becoming more in demand even to individual and casual users.
Squid proxies, in particular, appeal to users who want the two-in-one deal that it provides. It’s not only an efficient proxy server, it’s a dependable caching tool, too. There’s no need to install separate servers to gain the benefits of a single Squid proxy.
Frequently Asked Questions about find squid proxy server
How do I access Squid proxy server?
Install Proxy Server: Squid ProxyStep1: Update the server sudo yum update -y.Step 2: Configure EPEL repo. … Step 3: Install squid sudo yum -y install squid.Step 4: Start and enable squid server. … Step 5: Check the status of squid server. … Step 1: Install httpd-tools sudo yum -y install httpd-tools.More items…•Aug 11, 2018
Is squid a proxy server?
Squid is a Unix-based proxy server that can do both caching and proxying. It can cache any web content to the user or requestor that is from a closer data storage point. It frequently caches large media files and web pages to reduce bandwidth congestion. Thus it decreases loading periods.May 27, 2021
How do I find my squid proxy version?
We used the squid command with the -v option to find out the version of Squid installed on our machine, and the options used with the configure command before compiling Squid.
