Q. 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
How do I configure squid content filtering?
A. You can 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</TITLE> </HEAD> <BODY> <H1>File is blocked due to new IT policy</H1> <p>Please contact helpdesk for more information:</p> Phone: 555-12435 (ext 44)<br> Email: helpdesk@yourcorp.com<br>
Caution: Do not include HTML close tags </HTML> </BODY> 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:
# /etc/init.d/squid restart
Squid in action:
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