Squid Content Filtering !!!!!!!!

Sometimes for security reasons and to save bandwidth we would like to configure Squid proxy server in such way that no user can download the following files:

MP3
MPEG
MPG
AVG
AVI
EXE

For the solution we need to use squid ACL (access control list) to block all these files easily.

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

First open squid.conf file /etc/squid/squid.conf:

# vi /etc/squid/squid.conf
Now add following lines to your squid ACL section:

acl blockfiles urlpath_regex "/etc/squid/blocks.files.acl"

You want display custom error message when a file is blocked:

# Deny all blocked extension
deny_info ERR_BLOCKED_FILES blockfiles
http_access deny blockfiles

Save and close the file.

Create custom error message HTML file called ERR_BLOCKED_FILES in /etc/squid/error/ directory or /usr/share/squid/errors/English directory.

# vi ERR_BLOCKED_FILES

Append following content:

HTML>
HEAD>
TITLE>ERROR: Blocked file content
HEAD>
BODY>
H1>File is blocked due to new IT policy
p>Please contact stn authority for more information:
Phone: 9988554422 (ext 44)

Email: stnchandigarh@stn.edu

Caution: Do not include HTML close tags as it will be closed by squid.
Now create /etc/squid/blocks.files.acl file:

# vi /etc/squid/blocks.files.acl

Append following text:
\.[Ee][Xx][Ee]$
\.[Aa][Vv][Ii]$
\.[Mm][Pp][Gg]$
\.[Mm][Pp][Ee][Gg]$
\.[Mm][Pp]3$

Save and close the file.

Restart Squid:
# service squid restart


Squid in action: