Cisco ASA 5505 - Manual (Page 909)

43-33
Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter 43 Configuring Inspection of Basic Internet Protocols
SMTP and Extended SMTP Inspection
hostname(config-pmap-c)# {[drop [send-protocol-error] |
drop-connection [send-protocol-error]| mask | reset] [log] | rate-limit message_rate}
Not all options are available for each match or class command. See the CLI help or the command
reference for the exact options available.
The drop keyword drops all packets that match.
The send-protocol-error keyword sends a protocol error message.
The drop-connection keyword drops the packet and closes the connection.
The mask keyword masks out the matching portion of the packet.
The reset keyword drops the packet, closes the connection, and sends a TCP reset to the server
and/or client.
The log keyword, which you can use alone or with one of the other keywords, sends a system log
message.
The rate-limit message_rate argument limits the rate of messages.
You can specify multiple class or match commands in the policy map. For information about the order
of class and match commands, see the
“Defining Actions in an Inspection Policy Map” section on
page 33-2 .
Step 6 To configure parameters that affect the inspection engine, perform the following steps:
a. To enter parameters configuration mode, enter the following command:
hostname(config-pmap)# parameters
hostname(config-pmap-p)#
b. To configure a local domain name, enter the following command:
hostname(config-pmap-p)# mail-relay domain-name action [drop-connection | log]]
Where the drop-connection action closes the connection. The log action sends a system log
message when this policy map matches traffic.
c. To enforce banner obfuscation, enter the following command:
hostname(config-pmap-p)# mask-banner
The following example shows how to define an ESMTP inspection policy map.
hostname(config)# regex user1 “[email protected]”
hostname(config)# regex user2 “[email protected]”
hostname(config)# regex user3 “[email protected]”
hostname(config)# class-map type regex senders_black_list
hostname(config-cmap)# description “Regular expressions to filter out undesired senders”
hostname(config-cmap)# match regex user1
hostname(config-cmap)# match regex user2
hostname(config-cmap)# match regex user3
hostname(config)# policy-map type inspect esmtp advanced_esmtp_map
hostname(config-pmap)# match sender-address regex class senders_black_list
hostname(config-pmap-c)# drop-connection log
hostname(config)# policy-map outside_policy
hostname(config-pmap)# class inspection_default
hostname(config-pmap-c)# inspect esmtp advanced_esmtp_map
hostname(config)# service-policy outside_policy interface outside