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Preventing attacks
Increasing productivity by identifying spam email
Troubleshooting antivirus protection
By configuring the antivirus feature of the security gateway, you have fine-grained control over the
email attachments and files that come through your security gateway; however, the combination of the
different scanning mechanisms can inadvertently block content you really need to receive.
The most common problem with antivirus transfers is that the file is not downloaded in its entirety
because of a timeout. If you experience this problem, use the following techniques:
Increasing productivity by identifying spam email
Spam is unsolicited bulk email, most often advertising messages for a product or service. Spam email
wastes user productivity and consumes network and mail server resources. The security gateway
provides scanning processes that let you identify spam. You can also configure how to respond to spam
email.
When enabled, the security gateway scans email that arrives through the SMTP protocol. If your
organization permits users to retrieve email from external mail servers, you can also scan mail that is
handled by the POP3 protocol. You enable the antispam settings for each protocol on a rule-by-rule
basis.
Email that arrives at the security gateway by way of the SMTP protocol is scanned before it is
delivered; therefore, blocking a message is possible. Email that uses the POP3 protocol can only be
scanned after it has been delivered to a mailbox, but before it is read by a user. You cannot block POP3
email, because there is no way to remove the infected mail from the mailbox.
Email messages that are identified as spam are automatically logged. This lets you monitor what
percentage of mail passing through the gateway is identified as spam.
You must have a valid Content Security license to enable the heuristics scanning and subject pattern
matching processes. All of the other antispam processes require a Firewall Base license.
“Understanding and using licenses”
This section includes the following topics:
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About the antispam scanning process
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■
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Adding antispam protection to a rule
Enable data comforting if it is not already enabled.
“Avoiding potential session time-out
If you have problems transferring files of a particular file type,
add that file type to the list of files that are not scanned.
This is not advised for a single file transfer; no files with the
excluded extension are scanned while this setting is in effect.
“Specifying file types to scan”
Change the comforting settings for the transfer protocol to lower
the wait time and trickle rate. (Data comforting is not available for
SMTP.)
“Avoiding potential session time-out
Create a specific rule that does not use antivirus or DDR scanning
for this particular traffic.
This is the preferred method for a single file transfer because it is
easy to remove.
Содержание Security 5600 Series, Security 5400 Series,Clientless VPN 4400 Series
Страница 76: ...76 Managing administrative access Enabling SSH for command line access to the appliance...
Страница 242: ...242 Defining your security environment Controlling full application inspection of traffic...
Страница 243: ...243 Defining your security environment Controlling full application inspection of traffic...
Страница 269: ...268 Limiting user access Authenticating using Out Of Band Authentication OOBA...
Страница 319: ...318 Controlling traffic at the security gateway Blocking inappropriate content with content filtering...
Страница 373: ...372 Preventing attacks Enabling protection for logical network interfaces...
Страница 409: ...408 Providing remote access using VPN tunnels Multicast traffic through gateway to gateway IPsec tunnels...
Страница 509: ...508 Generating reports Upgrade reports...
Страница 553: ...552 Advanced system settings Configuring advanced options...
Страница 557: ...556 SSL server certificate management Installing a signed certificate...
Страница 861: ...860 Index...