Squid content filtering: Block / download of music MP3, mpg, mpeg, exec file by extensions

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For security reasons and to save bandwidth I would like to configure Squid proxy server such way that my users should not download all of the following files:
MP3
MPEG
MPG
AVG
AVI
EXE

How do I configure squid content filtering?

You need to use squid ACL (access control list) to block all files by extensions.

How do I block music files using squid content filtering ACL?

First open your squid.conf file /etc/squid/squid.conf, run:
# vi /etc/squid/squid.conf
Now add the following lines to your squid ACL section:

acl blockfiles urlpath_regex -i "/etc/squid/blocks.files.acl"
You want display custom error message when a file is blocked:
# Deny all blocked extension
error_directory /usr/share/squid/errors/English
deny_info ERR_BLOCKED_FILES blockfiles
http_access deny blockfiles
Save and close the file.Create a custom error message HTML file called ERR_BLOCKED_FILES in /etc/squid/error/ directory or /usr/share/squid/errors/English directory:
# vi /usr/share/squid/errors/English/ERR_BLOCKED_FILES
Append following content:

<HTML>
<HEAD>
<TITLE>ERROR: Blocked file content</TITLE>
</HEAD>
<BODY>
<H1>File is blocked due to new IT policy</H1>
<p>Please contact helpdesk for more information:</p>
<ul>
 <li>Phone: 555-12435 (ext 44)</li>
 <li>Email: helpdesk@nixcraft.com</li>
</BODY>
</HTML>

Now create a new file named /etc/squid/blocks.files.acl file:
# vi /etc/squid/blocks.files.acl
Append following text:
\.exe(\?.*)?$
\.avi(\?.*)?$
\.bat(\?.*)?$
\.tar(\?.*)?$
\.mpg(\?.*)?$
\.mp3(\?.*)?$
\.mp4(\?.*)?$
Save and close the file. Restart Squid:
# /etc/init.d/squid restart
Squid in action:

Fig.01: Squid in action
Fig.01: Squid in action

Say hello to rep_mime_type

To block Active Stream Format (Windows Media Player) and flash video format, add the following in your squid.conf:

acl media rep_mime_type x-ms-asf
acl mediapr urlpath_regex \.(afx|asf)(\?.*)?$

acl media rep_mime_type video/flv video/x-flv
acl mediapr urlpath_regex \.flv(\?.*)?$

http_access deny mediapr
http_reply_access deny media

Save and close the file. Reload squid server:
# systemctl reload squid
OR
# squid -k reconfigure

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

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83 comment

  1. I use squid but all my filterings is done via dansguardian. Bannerfilter is great to stop adverts. And web custome written based admin console keeps my non un*x admins happy

  2. In Squid, i want to do the routing through users?
    eg. user-a, user-b if user a can access internet then data transer through 246kbps line & if user-b access internet then it’s data transer through 1mbps line.
    [note:- user-a & user-b can set any where, any pc in network]

  3. Hi,
    I do the following configuration in squid but it is not possible to block the downloads.
    Plz give me the solution for this

    1. First u create acl where u’ll mention IP address to block,
      Then add rule to deny that acl.

      This may help u

      Umesh

  6. it worked for me , but it seems that still users are able to download files dont know how.
    how i can totally block the download from users.
    if u have downloading agent, then it by-pass and start download.
    How can i make it strong so that no one can download any thing through any software.

  7. Hi ,
    i was config my proxy successfully. But i can’t access my outlook. i think its prots are blocked.
    Then how can i unlock my outlook ports…
    If anybody konw the solution, Please Immediately send to me… my NAT server ip was given to the gateway of my proxy server and proxy server gateway was given to the users gateway.. Its correct or not ..
    If u know any other way….. please share with me…

    I want the correct solution immediately…

    MY personal EMAIL ID is saravanaprakasht@yahoo.com

  8. my office is blocked to down load mp3 files. Can you please help me how to down load mp3 files.

    Your favourable reply will be highly appreciated.

    Thanks in advance

    Das

  9. Dear Sir,

    I have followed your step-by-step instruction to block download files.

    i succesfully manage to block the files while clicking selected files. and i received error msg from squid.

    Unfortunately i still manage to download that file by simply using “Save Link As..” menu as i right click the mouse.

    it seem like users still manage to download prohibited file as configured in squid by using right click menu.

    please advice.

    regards

    amin

  10. Help!

    What if i want to…
    replace “Men at work” with “Aliens at party”

    Is this possible ?
    Can i do this in squid without using any addons ?

  11. This did not work at all. It is not blocking downloads. Yes one thing was possible that downloading by right clik and save target was stoped, rest all downloads are working. Not a good solution. Pls advise for another.

  12. is there away to unblock bebo cuz are school is gay and has filtered ALL the proxy sites to date
    thanks becci

  15. Hai friends pls help me in this

    I our Company we have 200 system and one linux server i want to configure squid in a way that no body should download files in my network and 2 to 3 system i should give premision to download can any body help me plzzzzzzzzzz.

  16. Is it possible to block downloads from yahoo mail and other web based email in Squid? I can block downloads using the instructions above but it can only block direct download from a site.

  18. The blocking file list can be simpler by adding “-i” to the blockfiles statement in squid.conf, that is:
    acl blockfiles urlpath_regex -i “/etc/squid/blocks.files.acl”

    # and in
    # /etc/squid/blocks.files.acl
    .exe$
    .avi$
    .mpg$
    .mpeg$
    .mp33$

  19. shankar, you can do it like this:
    in your squid.conf
    …
    acl special_grp src “/etc/squid/special_grp”
    acl blocked_files url_regex -i “/etc/squid/blocked_files
    …
    http_access allow special_grp blocked_files
    http_access deny !special_grp blocked_files
    …
    # make sure the above lines are above the line “http_access allow our_networks”

    in your /etc/squid/special_grp enter the ips of the systems (one ip per line) that you allow to download and in your /etc/squid/block_files enter the following content
    \.exe$
    \.avi$
    \.mpg$
    \.mpeg$
    \.mp3$

    Then reload squid and you are all set.

  20. it’s done by easy step like
    acl downloadfiles urlpath_regex -i “/etc/squid/downloadfiles.acl”

    http_access deny downloadfiles

  21. i want me to download mp3 of my choice but it is blocked.it just saves the file as HTML document rather than mp3 format how i can get rid of it.i use the intrnet provided by LAN of my company.

  22. Hi
    This is my first time to enter in to this forum.

    I want to block users to more than 5MB per day.How can I do so.
    I am using Lunix Fedora

    Regargs

  23. Hi everone,I had configure squid proxy server still it’s working but i need restrict to downloads for users can u help.already i am doing like.acl blickfile urlpath _ regix -i “/etc/squid/blocks.filies.acl”
    http_access deny blockfiles
    deny_info ERR_BLOCKED_FILES blockfiles acl
    iam creating file block.files.acl under squid
    mention all extention on that file like \.exe$
    after restarting the sevice
    but .exe file will downloaded . Can you help where exact problem found.

    Thanks
    venkat

  26. Dear All,
    I have done above procedure & it is working good, but there is a problem,
    It also blocked symantec live update, Kindly help me for allow symantec live update with these reistrictions.
    Thankx

  27. sir I want to configure the squid proxy server file in such a way that it contains one public IP and two private IP (EX 192.168.0.1 172.16.0.1 ) and and block various sites (I.E orkut.com , blocl exe file download etc) but in some ip there is no rule ; please tell me how can i configure that proxy server .

  28. Please help me configure

    Sir,in my company we have two gateways and need to give access only to few selected people in my office. and they need to configure through squid. Please help me… Can anyone help me. If so i would be thankful to them

    Bala

  29. Is this possibe that if a network/IP not allowed in squid try to come through his/her browser ( by using the squid IP in the browser) then his/her browser should display a message ( you are not allowed to come throught this proxy or any other message)

    Waiting .

    Regards,
    Ishtiaq Ahmed

  30. Hi
    Dear
    i am usind squid in linux for proxy server i want to block the downloading , music file of all types of extensions image file for user side please guide mein this regard. & also i want to block chatting all kinds of messangers.

  31. Dear
    how are you i am facing a problem regarding blocking of unwanted sites in my network using squid please help me in this regards. i want to block all kinds of messangers, chat sites musical sites & all other voulger sites. i am waiting for your quick response.

    Thanks

    Amjad Shaikh

  32. @ Amjad

    Hi , you need to create the acl for that I wll give you the syntax for that

    under acl tag write like this
    acl block url_regex “/etc/squid/squid-block.acl”
    and under http_access block
    http_access allow manager should be changed to http_access allow all
    http_access deny block
    and create a seperate file squid-block.acl and list out those unwanted sites and then reload the squid.
    Make sure that ur internet connection is made through proxy

    Regarding messanger and chat sites you need to use iptables

  35. Hi
    could some one please guide me that how to integrate the squid with Active directory to filter/ schedule the access to web based on the usernames (From Active directory)

  37. we have got wi-fi by college but we are unable to download any videoes or we can’t even see pictures.so suggest us..

  38. hi how r u .would u like to tell where we place this lines please
    can u send code with example

    http_access allow special_grp blocked_files
    http_access deny !special_grp blocked_files

  39. i block downloading on fedora 11.now i want to allow some ip to download and watch online movie
    how can i make white class of these ip

    plz inform with example

  40. Dear Sir,

    I have followed your step-by-step instruction to block download files.

    i succesfully manage to block the files while clicking selected files. and i received error msg from squid.

    Unfortunately i still manage to download that file by simply using “Save Link As..” menu as i right click the mouse.

    it seem like users still manage to download prohibited file as configured in squid by using right click menu.

    please advice.

    regards
    kushal

  41. Vivek,

    Is this the route one would take to create a music download service? By that I mean, if a user has not paid for certain music, they can be restricted from downloading a particular track or album, however if they have paid they are granted access. Also, if it is a shared environment with access only to a DB such as MySQL and a scripting language such as PHP, how would this be possible?

  42. Dear
    AOA
    How are you, i hope that you are fine , on my MINUX Machine an error messgae is dispalyed when i start the machine please solve my problem on urgent bases the error message is as “Maximum Memory Performance is achieved with matched DIMMS. The Installed amountof memory in Channel A is not equal to the amount of press any key to continue”

    i am waiting for your quick & positive reply.

    Amjad Zia

  43. Hello,
    I want to allow all sites accpect my live video streaming websits i.e youtube ,matacafe
    how i can able to do that plz spourt me

    Regarding
    omer

  44. Dear Mr. Atul,
    Can u help me , I want to access my apps server from internet (out side of my local area network). your help is highly thanfull.

    khalil mir

  45. hiiiiiiiii sir i want to block all porn website that can be access by user

    Regarding

    Manish Chaudhary

  50. hiiii sir
    i have done user authentication and contain filtering in squid proxy server it is working good but io want to restrict all porn website only for student user not for HCl user so how can i configure user base contain filtering
    Thanks and Regards
    Manish Chaudhary

    1. Manish,
      U can simply add deny rule for restriction on IP base.
      Select the user to restrict add an acl with all IP addresses, add deny rule for that Acl (name that ACL as Student_Access etc)

      This may solve your problem.

      Umesh

  55. How can I stop youtube videos from playing on the clients at my network without blocking the actual Website. Em using Squid Proxy server

  56. Hello all,

    I have different scenario. I have linux firewall and squid installed in different server.
    How can forward all lan clients to squid box from linux router, since forwarding from cisco router make squid box see all client coming from linux gateway ip. I want to see individual ip logs in squid box. How is it possible?

    cisco router
    |
    |
    Squid box (172.160.10.2)—–|——-Linux router (172.16.103)
    |
    eth1
    |
    LAN CLients (192.168.9.0/24)

  57. Hi Friends,

    I want to download a film form the internet but was block.
    Is there any possible solution?

  58. Hi I am new to this forum..Very useful for me where I blocked the contents using the above mentioned source codes. It works perfectly.

    But I need to allow the users to download a particular exe file alone. Help me how to do that in the squid.

    Help from anyone is highly appreciated.

  59. hi vivek,
    is it possible to customize squid to view download rates by the different IPs & manually terminating the downloads ?
    objective is to prevent big downloads (like movies,softwares) and not to penalise users requiring a small download of eg 3MB.

    Thanks,
    vicky [at] linuxmail.org

  60. dear,
    I want to give internet access control in my office. Now am using Ubuntu server and squid 2.7. I want to give access some web sites only to particular IP and want to give no internet access to some IPs. How it possible?

  61. i am use windows Xp 2000 kindly help me?
    how can i use download files becoz my office is block all downloading

  62. Hi experts please help me in blocking online games website using squid proxy. I tried many things. but nothing worked. I want to block miniclip.com and other flash games websites.

    Please help me with this.

  63. Hi, all
    I am using cent os 5.5 and my proxy server is squid server.

    My problem is i want to allow one of my users in the company can access a website http://www.youtube.com and none of the remaining should not access..

    client ip is 192.168.1.170
    website http://www.youtube.com

    only this 192.168.1.170 user should access this website

    Regards
    ratnakarreddy

  64. Hi,

    I have installed squid 3.0 in our network.
    everything is fine except, i am not able to open PDF files in my browser and Not able to attach files from gmail and yahoo.
    I have checked with upload size and download size. its correct.
    I think problem is with flash player or something else.
    Please provide me solution for the same.
    Thank you

  65. when i trying in this process in rhel 6 squid service is not start.
    squid service is failed.
    plz help me

  67. @naveen

    Please check the content of squid.out. This will tell you what is wrong with your squid.

  68. please help i have an internet cafe’, and i use windows 7, how can i use/install squid
    on it, to block those files.

  69. Can somebody give me the code on how to disable images from displaying on the browser. I was able to do this a long time ago in my squid. but i can not remember anymore.. I hope to hear a responce from anyone.. thank you…

  71. For security and to save bandwidth I would like to configure Squid proxy server such way that I do not want my users to download all of the following files:
    MP3
    MPEG
    MPG
    AVG
    AVI
    EXE

    1. Torrent cant be blocked by squid.
      I see Intrusion Prevention System like SNORT/SURICATA have capability to detect and block torrent traffic based on signitures.
      Still torrent can make its own way.

      The best practice is you can block LAN User/IP address completly for 15-20 minutes who found having torrent traffic.

  76. have installed squid 3.0 in our network.
    everything is fine except, i am not able to open PDF files in my browser and Not able to attach files from gmail and yahoo.
    I have checked with upload size and download size. its correct.
    I think problem is with flash player or something else.
    Please provide me solution for the same.

  77. can anyone tell me how to restrict the download and upload limit to 5 mb in squid.
    file more than 5 mb should not be downloaded

  78. Is there any guide about blocking files by their signatures using squid ?
    I want to write my own code to check if a file have the specific signature and block it if necessary and use this code with squid.
    Will really appreciate any help.

  79. this can help to block file types.

    acl blockExtensions rep_mime_type -i “/etc/squid/extension.acl”
    http_reply_access deny blockExtensions

    file contain of “/etc/squid/extension.acl”

    ^application/octet-stream
    ^audio/mpeg
    ^video/x-msvideo

    this will block :
    application/octet-stream (.exe, .bz2, .core, .cab, etc..)
    audio/mpeg (.mp2, .mp3, .mpga )
    video/x-msvideo (.avi)

    you can add more file types to block by ref. from mime.conf file.

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