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Advanced Anti-Spam Options
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Advanced Anti-Spam
Options
Click the Advanced button to reveal the following advanced Anti-Spam
options.
RBL (Realtime Blackhole
List)
RBLs contain the addresses of known sources of spam and are
maintained by both commercial and non-commercial organizations.
The RBL mechanism is based on DNS. Every server that attempts to
connect to the 3Com Email Firewall will be looked up on the specified
RBL servers using DNS. If the server is blacklisted, then the server is
considered an origin of known spam and the connection dropped.
Note the following considerations when using RBL:
■
If the RBL server is not available, the DNS request times out. This may
affect performance and requires monitoring for timed-out
connections.
■
If a message that you want to receive is blocked by an RBL, add an
item to the
Pattern Based Message Filtering
list to “Trust” (to train for
STA) or “Accept” (not train for STA) this message.
■
Enable RBLs — Select this check box to enable RBLs.
■
Check Relays — The Check Relays setting deals with spammers who
are relaying their messages through an intermediate server. The
information about the originating server is carried in the headers of
the message which is checked against the RBL. For example, set
Check
Relays
to “2” to look for the last two relays.
■
Action — Specify one of the following actions:
■
Just log: An entry is made in the log and no other action is taken.
■
Modify Subject Header: The text specified in Action Data will be
inserted into the message subject line.
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Страница 8: ......
Страница 12: ...12 ABOUT THIS GUIDE ...
Страница 30: ...30 CHAPTER 2 CONFIGURING MAIL DELIVERY ...
Страница 46: ...46 CHAPTER 3 CONFIGURING MAIL SECURITY ...
Страница 98: ...98 CHAPTER 6 SYSTEM CONFIGURATION ...
Страница 114: ...114 CHAPTER 7 SYSTEM MANAGEMENT ...
Страница 144: ...144 APPENDIX C THIRD PARTY COPYRIGHT AND LICENSE AGREEMENTS ...