Cisco Cisco Email Security Appliance C160 Guía Del Usuario
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AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide
Chapter 9 Using Message Filters to Enforce Email Policies
Message Filter Rules
Recipient Count Rule
The
rcpt-count
rule compares the number of recipients of a message against an integer value, in a
similar way to the
body-size
rule. This can be useful for preventing users from sending email to large
numbers of recipients at once, or for ensuring that such large mailing campaigns go out over a certain
Virtual Gateway address. The following example sends any email with more than 100 recipients over a
specific Virtual Gateway address:
Virtual Gateway address. The following example sends any email with more than 100 recipients over a
specific Virtual Gateway address:
Address Count Rule
The
addr-count()
message filter rule takes one or more header strings, counts the number of recipients
in each line and reports the cumulative number of recipients. This filter differs from the
rcpt-count
filter rule in that it operates on the message body headers instead of the envelope recipients. The
following example shows the filter rule used to replace a long list of recipients with the alias,
“undisclosed-recipients”:
following example shows the filter rule used to replace a long list of recipients with the alias,
“undisclosed-recipients”:
load_balance_b:
if (random(2)) {
alt-src-host('interface_a');
} else {
alt-src-host('interface_b');
}
large_list_filter:
if (rcpt-count > 100) {
alt-src-host('mass_mailing_interface');
}
count: if (addr-count("To", "Cc") > 30) {
strip-header("To");
strip-header("Cc");
insert-header("To", "undisclosed-recipients");
}