ANTISPAM
The antispam configuration screen consists of 3 tabs:
l General : Basic configuration of the Antispam module (activation, SMTP parameters,
Reputation-based analysis, etc).
l Whitelisted domains: contains the list of domains that must be systematically considered
legitimate.
l Blacklisted domains: contains the list of domains that must be systematically considered
spam senders.
“General” tab
The antispam module can be enabled by determining the analyses to be enabled. Two options
are available on the firewall:
Enable reputation-
based analysis (DNS
blacklists - RBL)
This option allows validating the sender by comparing against a public list of known
spam senders (DNSBL).
Enable heuristic
analysis
This option allows examining the contents of the e-mail to determine its impact.
SMTP parameters
The trusted server concerns the SMTP server. By filling in this field, which is optional, e-mails will
be analyzed more thoroughly by the Antispam module.
SMTP server domain
name (FQDN)
This optional field allows defining a “trusted” domain.
Mail relayed by a server belonging to the domain indicated therefore avoids the
domain scan. This may be defined for mail relayed by internal servers, for example.
SMTP allows mail relay servers to fill in a field indicating their identity. If mail passes
through a server belonging to the trusted domain, the earlier servers will be
considered legitimate and the scan will only apply to the following servers.
Action There are 4 possible actions that will allow the SMTP proxy to respond to the remote
SMTP server by indicating that the message has been rejected as it is spam.
l Tag as spam: e-mails will not be blocked but will be tagged as spam.
l Block all spam messages: the e-mail will be rejected regardless of the level of trust.
l Block all spam messages at Level 2 or higher: this option allows defining that
beyond the trust threshold of Level 2, an e-mail will be rejected. The thresholds are:
“1 – Low”, “2 – Medium”, “3 – High”.
l Block only Level 3 spam messages: this option allows defining that beyond the
trust threshold of Level 3 (High), the e-mail will be rejected.
For example, if you set a limit of 100 for the heuristic analysis, e-mails with a score higher than
100 will be considered spam. From 100 to 200, the level of trust will be low, from 200 to 300 it will
be moderate and above 300, it will be high. If you have indicated a moderate level of trust for this
option, all e-mails of moderate and high level (above 200) will be rejected whereas those from
100 to 200 will be kept.
Page 36/448 sns-en-user_configuration_manual-v3 - Copyright © Stormshield 2016
SNS - USER CONFIGURATION MANUAL V.3
ANTISPAM
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