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14.5.3 SPAM/Virus/Malware 371
You can add a complete email address (e.g. user@example.com) to prevent filtering
emails from this specific address. If you want to allow every email from a specific domain
to pass, add only the domain part of the address (e.g. example.com).
14.5.3-J SPAM modules
The settings made on this screen will not only apply to the relay SPAM filter, but also
to the user specific SPAM filter as configured in the user administration.
DNS based lists
Several blacklists are available in the Internet, which contain mail servers known to be
the origin of SPAM mails. Another form of blacklists contains web server addresses
that are advertised by SPAM mails (URI: URI Black Lists). Links in the message body
are checked against these URI Black Lists. Finally there are also whitelists with friendly
mail servers.
When analyzing an email, some of these lists can be queried. Each single hit will
be rated with a rather moderate value. However when multiple lists indicate potential
SPAM, it will have considerable impact on the SPAM score. The reliability of the lists
depends on how the entries have been collected. Choose which level of quality will
be considered.
few
Select this option if you want to include only verified SPAM sources. Particularly
automatically collected lists will not be considered. URI Black Lists are active.
medium
In addition to verified SPAM sources this level will also include addresses
collected automatically by SPAM traps.
many
If you choose this option, emails from known dynamic IP addresses will be scored,
too.
Razor2 distributed spam filter network
This feature will calculate a fuzzy checksum of some parts of an email and send it
to Razor2 servers in the Internet (TCP port 2703). Razor2 provides a database with
the checksums of known SPAM. In case of a match, the SPAM score of the mail is
increased. The amount depends on the reputation of those, who reported the SPAM
mail to the Razor2 system.