The web proxy in ClearOS is a high-performance proxy caching server for web clients, supporting HTTP, FTP and some lesser known protocols. The software not only saves bandwidth and speeds up access time, but also gives administrators the ability to track web usage via web-based reports.
If you are new to ClearOS and/or setting up a proxy server, you may want to refer to the Guide to Setting up Web Proxy, Content Filter and Access Control Guide.
If your system does not have this app available, you can install it via the Marketplace.
You can find this feature in the menu system at the following location:
If you would like to require a username/password for web access, you can enable user authentication.
In transparent mode, all web requests from the local network automatically pass through the proxy. The advantage: no configuration changes are required on the workstations. The disadvantage: secure web sites (HTTPS) can not flow through the proxy.
Since network traffic needs to be intercepted before going out the Internet, this his mode is only available when ClearOS is configured as a gateway.
The Performance Level indicates the size of network that your system can support. The Community Edition is designed for home/small networks and is already optimized for 10 users or less. The Professional Edition does automatic optimization based on available system resources.
Maximum Cache Size
The maximum size on your hard disk to use for the proxy server cache.
Maximum Object Size
Any file (image, web page, PDF, etc) above the maximum object size will still go through the proxy but will not be cached. Large files (for instance, a movie file) can take up a lot of space in your proxy cache. If you have a cache size of 2 Gb and two people happen to download 1 Gb files at the same time, then these two files would replace everything else in your cache. You can limit the maximum object size to prevent this kind of scenario.
Maximum Download File Size
If you want to limit downloads of large files (for instance, movies) you can set a maximum size. Any file above this size limit will get blocked.
Web Site Bypass
In some circumstances, you may need to by-pass the proxy server. Typically, this is required for web sites that are not proxy-friendly. Some notable examples:
- Older Microsoft IIS web servers send invalid web server responses
- Microsoft IIS web servers can be configured with non-standard authentication
- Tivo personal video recorders (PVRs) are unable to connect via a proxy server. Adding Tivo's network 188.8.131.52/14 to the proxy by-pass list solves the issue.
You can use the following format for the bypass:
- Web site name
- IP address
- Network Notation (recommended)
If you are running the proxy in non-transparent mode, then you also have to adjust your web browser's proxy server settings. The web site or IP address that you add to the ClearOS web proxy bypass list should also be added to your browser's proxy exception list.
Web Browser Configuration
In non-transparent mode, you must change the settings on all the web browsers running on your local network. The following describes the steps for configuring Internet Explorer, but other browsers have similar procedures. In Internet Explorer
- Click on in the menu bar
- Select Internet Options
- Click on the tab
- Click on the button
In the Proxy Server settings box, specify your ClearOS IP address and the proxy port (see next section). You may not be able to access websites on your system or local network unless you select bypass proxy server for local addresses.
Which Port Should I Use?
So which port should be configured in your web browser's proxy settings?
- Are you using transparent mode? If yes, then no web browser changes are required! If not, continue.
- Are you using the content filter? If yes, use port 8080. If no, use port 3128.
From the Squid Web Proxy FAQ:
Question: Can I make my regular FTP clients use a Squid cache?
Answer: It's not possible. Squid only accepts HTTP requests.
Requested web page or file is too large
If you see the message Requested web page or file is too large in your web browser, change the Maximum Download File Size parameter described above.