F-Secure Internet Gatekeeper for Linux/Administrator’s Guide
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Spam filtering method
SPAM detection method
Specifies the spam filtering method. The line "X-Spam-Status: Yes(<product name>) with
[<detection name>]" is added to the e-mail header if the mail is classified as spam.
If an e-mail matches multiple conditions, scanning is performed in the sequence: custom rules,
spam detection engine, RBL, SURBL.
Custom filtering rules
Custom filtering rules
Specifies individual rules for identifying spam.
The detection name for the custom rules is "FSIGK/SPAM_LIST/CUSTOM/(rule
number)/(detected header field name)".
You can specify up to 100 custom rules. You can also specify multiple character strings to
scan for in each rule.
If you have enabled
Custom filtering rules
, the line "CUSTOM <tab>custom.txt" is added
to /opt/f-secure/fsigk/conf/spam/files.txt.
Edit the custom filtering rules
Edit the custom filtering rules
Use
Edit the custom filtering rules
to edit the list of spam filtering rules. An e-mail is
classified as spam if it matches any of the specified conditions. Because the custom
rules are applied first, before other filtering methods, the rules can be used as a black list
and white list.
The list of rules is checked starting from the top. The different conditions that can be
specified are described below. Please restart the service from the proxy's web console
screen after editing these settings.
Field name
Specifies where to apply the rule. The available settings are described below.
•
Designated header field
Applies the rule to specific header fields. If the field you want to specify is not in the
list, select (Other...) and enter the field name in the “Other” field. You can enter up
to 29 characters. The field name is not case sensitive.
•
File name
Applies the rule to the name of attached files.
•
File size
Applies the rule to the size of attached files. The condition is specified as a number
of bytes. This performs a character string comparison. It does not test whether the
numerical value is larger or smaller.
•
Text body
Applies the rule to character strings in the e-mail's text body.
•
HTML body
Applies the rule to character strings in the e-mail's HTML body. Carriage returns
are treated as space characters.
•
Linked host
Applies the rule to the host name part of the URLs contained in the e-mail.
•
Relay address
Applies the rule to the IP addresses in the Received field. In SMTP scanning, the
rule is applied also to the source IP address.