Cisco Cisco Email Security Appliance C170 Guia Do Utilizador
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User Guide for AsyncOS 10.0 for Cisco Email Security Appliances
Chapter 9 Using Message Filters to Enforce Email Policies
Message Filter Rules
When working with headers, remember that the current value of the header includes changes made
during processing (such as with filter actions that add, remove, or modify message headings). See
during processing (such as with filter actions that add, remove, or modify message headings). See
for more information.
Random Rule
The
random
rule generates a random number from zero to N-1, where N is the integer value supplied in
parenthesis after the rule. Like the
header()
rule, this rule may be used in a comparison, or may be used
alone in a “unary” form. The rule evaluates to
true
in the unary form if the random number generated
is non-zero. For example, both of the following filters are effectively equal, choosing Virtual Gateway
address A half the time, and Virtual Gateway address B the other half of the time:
address A half the time, and Virtual Gateway address B the other half of the time:
strip-header('X-DeleteMe');
}
load_balance_a:
if (random(10) < 5) {
alt-src-host('interface_a');
} else {
alt-src-host('interface_b');
}
load_balance_b:
if (random(2)) {
alt-src-host('interface_a');
} else {
alt-src-host('interface_b');
}