How To Control Download Of Files And Mime Types In SafeSquid Proxy Server

Administrators regularly find themselves in troubled situations, when irresponsible users waste their productive time and Internet bandwidth, on online music, radio, video or downloading large, non-productive contents. They also, knowingly or unknowingly, put other serious users to inconvenience and put the network at risk.  Administrators can avoid such situations by controlling what content is allowed or denied, and when. 

SafeSquid has a unique Mime Filter. Mime Filter allows you to create rules that define the nature of the content that may be accessed from the Internet. You can create rules for generically blocking or allowing any content that is application, audio, image, message, model, multipart, text, video, as per IANA standards. You can also - implement your own standards or; create rules for a specific file-type.

In this tutorial I will explain how you can block access to specific files using Mime filter. In my earlier tutorials, I have already explained how to create user, group and application profiles. So I will not go into details about profiles, and assume that the reader already knows about profiles. Readers who are not aware of profiles, can refer to the earlier tutorials from the list at the bottom of this tutorial. 

Open the SafeSquid Web Interface and go to Config => Mime filtering

You will see a screen similar to this:

Mime Filtering Section

Like all other sections, Mime filtering can also be enabled or disabled by setting Enabled to Yes or No respectively. Enable the section if it is disabled. When the Policy is Allow, all file-types or mime-types are allowed, and you define what is to be blocked under the Deny sub-section. When the Policy is Deny, all file-types or mime-types are denied, and you define what is to be allowed under the Allow sub-section. We will leave the Policy to Allow.

To block access to files based on their extensions, click on Add under the Deny sub-section. The following figure shows the screen that appears -

Adding file extentions in Mime Filtering

Simply fill in the fields as they appear in the figure, replacing the file extensions with the once that you would like to block access to. If you would like to apply this rule to only specific users / groups, mention their user profile in the Profiles field. If you leave the Profiles field blank, the rule will apply to all users.

If you would like to deny access to the specified file types only from specific websites, then type list of websites in the Host field, in this format -

(orkut\.com|flixster\.com|youtube\.com)

Similarly, to block access to files based on their mime-type, fill in the Mime type field as shown in the figure below -.

Adding mime-type in Mime Filtering

For a list of mime-types, see http://www.w3schools.com/media/media_mimeref.asp

To create a more comprehensive rule, you can use the Profiles section to create a profile, and then use it in the Mime filtering section, to take desired action. For example, if you wanted to block all audio & video files during office hours (0900-1700), and allow access during lunch (1300-1400), before and after office hours, you could create the following profiles: 

The first rule will apply the profile block-audio-video to requests for audio and video contents during 0900-1300 hrs. The second rule will do the same, but during 1400-1700 hrs. Now in the Mime filtering section, just create a rule in the Deny sub-section to block access to the block-audio-video profiles.

If you would like to allow audio/video content from some specific business websites, then create a rule in profile section below the above rules, specify the websites in the Hosts field, and specify block-audio-video in the Removed profiles field.

This will remove the profile block-audio-video from the specified websites, and allow access to audio and video contents from these sites.

Also see:

Deploying A Content Filtering Proxy Server To Distribute Controlled Internet Access With SafeSquid

Set Up Gateway Level Virus Security With ClamAV And SafeSquid Proxy

How To Set Up Internet Access Control And Internet Filtering With SafeSquid Proxy Server

How To Control Access To Unwanted Websites Using URL Blacklist With SafeSquid Proxy Server

How To Configure Granular Bandwidth Management Rules In SafeSquid Proxy Server

How To Block Ads And Banners In SafeSquid Proxy Server

How To Block Cookies From Unwanted Websites With SafeSquid Proxy Server

Enhance Security By Removing ActiveX Control Codes From Web Pages With SafeSquid Proxy Server

How To Block WebPages Based On Keywords Or Phrases With SafeSquid Proxy Server

How To Control Or Block Instant Messengers With SafeSquid Proxy Server

How To Block Porn Pictures And Images With SafeSquid Proxy Server

How To Enforce Google SafeSearch With SafeSquid Proxy Server

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