ZyXEL Communications ZyWALL USG Series, Reference Manual

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Chapter 36 Anti-Spam
ZyWALL / USG (ZLD) CLI Reference Guide
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• The wildcard can be anywhere in the text string and you can use more than one wildcard. You
cannot use two wildcards side by side, there must be other characters between them.
• The ZyWALL / USG checks the first header with the name you specified in the entry. So if the e-
mail has more than one “Received” header, the ZyWALL / USG checks the first one.
36.2.3 DNSBL Anti-Spam Commands
This section describes the commands for checking the sender and relay IP addresses in e-mail
headers against DNS (Domain Name Service)-based spam Black Lists (DNSBLs). You must use the
configure terminal
command to enter the configuration mode before you can use these
commands.
The following table identifies the values required for many of these commands. Other input values
are discussed with the corresponding commands.
This table describes the DNSBL commands.
Table 144
Input Values for DNSBL Commands
LABEL DESCRIPTION
dnsbl_domain
A domain that is maintaining a DNSBL. You may use 0-254 alphanumeric characters, or
dashes (-).
Table 145
DNSBL Commands
COMMAND DESCRIPTION
[no] anti-spam dnsbl activate
Turns DNSBL checking on or off.
anti-spam dnsbl [1..5] domain
dnsbl_domain {activate|deactivate}
Adds or edits a DNSBL domain for checking e-mail header IP addresses.
no anti-spam dnsbl domain dnsbl_domain
Removes the specified DNSBL domain.
anti-spam dnsbl query-timeout smtp {drop
| forward | forward-with-tag}
Sets how the ZyWALL / USG handles SMTP mail (mail going to an e-mail
server) if the queries to the DNSBL domains time out.
anti-spam dnsbl query-timeout pop3
{forward | forward-with-tag}
Sets how the ZyWALL / USG handles POP3 mail (mail coming to an e-mail
client) if the queries to the DNSBL domains time out.
anti-spam dnsbl max-query-ip [1..5]
Sets up to how many sender and relay server IP addresses in the mail
header to check against the DNSBL.
anti-spam dnsbl ip-check-order {forward
| backward}
Configures the order in which anti-spam checks e-mail header IP
addresses against the DNSBLs.
•
forward
checks the first N IP addresses. Checking starts from the first
IP address in the mail header. This is the IP of the sender or the first
server that forwarded the mail.
•
backward
checks the last N IP addresses. Checking starts from the
last IP address in the mail header. This is the IP of the last server that
forwarded the mail.
anti-spam tag {dnsbl | dnsbl-timeout}
[ tag ]
dnsbl
configures the message or label to add to the beginning of the mail
subject of e-mails that have a sender or relay IP address in the header
that matches a blacklist maintained by a DNSBL domain listed in the
ZyWALL / USG.
dnsbl-timeout
configures the message or label to add to the mail
subject of e-mails that the ZyWALL / USG forwards if queries to the
DNSBL domains time out.
Use up to 15 alphanumeric characters, underscores (_), colons (:), or
dashes (-).
show anti-spam dnsbl status
Displays the activation status of the anti-spam DNSBL checking.