User guide

User Guide 135
Proxy Settings
FTP proxy: Upload and download content
You can control the type of files that the FTP proxy allows for downloads and uploads. For example, because
many hackers use executable files to deploy viruses or worms on a computer, you could select to deny
requests for *.exe files. Or, if you do not want to let users upload Windows Media files to an FTP server, you
could add *.wma to the proxy definition and specify that these files are denied. Use the asterisk (*) as a wild
card.
1. Select the FTP Content tab.
2. In the Downloads text box, select the Deny these file types check box if you want to limit the types
of files that a user can download.
This check box is selected by default and restricts the types of files that users can download through the FTP proxy.
3. If you want to deny additional files or file types, type an asterisk (*) and the file name or extension, and
then click Add.
4. In the Uploads text box, select the Deny these file types check box if you want to limit the types of
files that a user can upload. If you select this setting, the files listed will not be allowed.
5. If you want to deny any additional files or file types, type an asterisk (*) and the file name or extension,
and then click Add.
6. Click Submit.
About the POP3 proxy
POP3 (Post Office Protocol v.3) is a protocol that moves email messages from an email server to an email client
on a TCP connection on port 110. Most Internet-based email accounts use POP3. With POP3, an email client
contacts the email server and checks for any new email messages. If it finds a new message, it downloads the
email message to the local email client. After the message is received by the email client, the connection is
closed.
With a POP3 proxy filter you can:
 Adjust timeout and line length limits to stop the POP3 proxy from using too many network resources
and to prevent some types of attacks.
 Customize the deny message that users see when an email they try to receive is blocked.
 Filter content embedded in email with MIME types.
 Block specified path patterns and URLs.
To enable the POP3 proxy, see Enable a proxy
. Then, if you choose, edit the proxy definition as described in
Add or edit a proxy policy
.
Edit the POP3 proxy
To change the default settings of the POP3 proxy, select Firewall > Outgoing from the navigation menu. Find
the POP3 proxy and click Edit. Make sure you look at all tabs of the POP3 proxy configuration. The Properties
tab shows you what port and protocol the proxy uses. You can change the port and protocol on this tab if
necessary.