Cisco Cisco Email Security Appliance C170 Guia Do Utilizador
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User Guide for AsyncOS 9.7 for Cisco Email Security Appliances
Chapter 9 Using Message Filters to Enforce Email Policies
Message Filter Examples
Alter SRBS Filter
Alter the (SenderBase Reputation Score) SBRS threshold for certain domains:
Filename Regex Filter
This filter specifies a range of size for the body of the message, and looks for an attachment that matches
the regular expression (this matches files named “readme.zip”, “readme.exe”, “attach.exe”, and so
forth.):
the regular expression (this matches files named “readme.zip”, “readme.exe”, “attach.exe”, and so
forth.):
Show SenderBase Reputation Score in Header Filter
Remember to log the headers (see the “Logging” chapter) so they appear in the mail log:
Insert Policy into Header Filter
Show which mail flow policy accepted the connection:
mod_sbrs:
if ( (rcpt-count == 1) AND (rcpt-to == "@domain\\.com$") AND (reputation < -2) ) {
drop ();
}
filename_filter:
if ((body-size >= 9k) AND (body-size <= 20k)) {
if (body-contains ("(?i)(readme|attach|information)\\.(zip|exe)$")) {
drop ();
}
}
Check_SBRS:
if (true) {
insert-header('X-SBRS', '$Reputation');
}
Policy_Tracker:
if (true) {