Cisco Cisco FirePOWER Appliance 8130

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FireSIGHT System User Guide
 
Chapter 25      Using Application Layer Preprocessors 
  Decoding SMTP Traffic
Note also that when the values for the 
Base64 Decoding Depth
7-Bit/8-Bit/Binary Decoding Depth
Quoted-Printable Decoding Depth
, or 
Unix-to-Unix Decoding Depth
 options are different in an intrusion policy 
associated with the default action of an access control policy and intrusion policies associated with 
access control rules, the highest value is used. See 
, and 
 for more information.
If no preprocessor rule is mentioned, the option is not associated with a preprocessor rule.
Ports
Specifies the ports whose SMTP traffic you want to normalize. You can specify an integer from 0 to 
65535. Separate multiple ports with commas.
Note
Any port you add to the SMTP 
Ports
 list should also be added to the TCP client reassembly 
list for each TCP policy. For more information on configuring TCP reassembly ports, see 
Stateful Inspection
When selected, causes SMTP decoder to save state and provide session context for individual 
packets and only inspects reassembled sessions. When cleared, analyzes each individual packet 
without session context.
Normalize
When set to All, normalizes all commands. Checks for more than one space character after a 
command.
When set to None, normalizes no commands.
When set to Cmds, normalizes the commands listed in 
Custom Commands
.
Custom Commands
When 
Normalize
 is set to Cmds, normalizes the listed commands. 
Specify commands which should be normalized in the text box. Checks for more than one space 
character after a command. 
The space (ASCII 0x20) and tab (ASCII 0x09) characters count as space characters for 
normalization purposes. 
Ignore Data 
Does not process mail data; processes only MIME mail header data.
Ignore TLS Data
Does not process data encrypted under the Transport Layer Security protocol.
No Alerts 
Disables intrusion events when accompanying preprocessor rules are enabled.
Detect Unknown Commands
Detects unknown commands in SMTP traffic.
You can enable rules 124:5 and 124:6 to generate events for this option. See 
 for more information.