Enabling Maximum Forward Field Validation - Cisco 4700M Configuration Manual

Chapter 3 Configuring Application Protocol Inspection
Note

Enabling Maximum Forward Field Validation

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To disable instant messaging, enter:
host1/Admin(config-parammap-sip)# no im
Disabling IM results in the ACE dropping all messages that belong to the IM.
The Max-Forwards header field limits the number of hops that a SIP request can
take on the way to its destination. This header field contains an integer that is
decremented by one at each hop. If the Max-Forwards value reaches zero before
the request reaches its destination, the request is rejected with a 483 Too Many
Hops error response. You can instruct the ACE to validate the Max-Forwards
header field value and to take appropriate action if the validation fails.
To instruct the ACE to validate the value of the Max-Forwards header field, use
the max-forward-validation command in parameter map configuration mode.
The syntax of this command is as follows:
max-forward-validation {log} | {{drop | reset} [log]}
The keywords and options are as follows:
log—Specifies that the ACE log a max forward validation event.
•
drop—Specifies that the ACE drop the SIP message.
•
reset—Specifies that the ACE reset the SIP connection.
•
For example, to enable Max-Forwards header field validation, enter:
host1/Admin(config-parammap-sip)# max-forward-validation drop log
To disable maximum forward field validation, enter:
host1/Admin(config-parammap-sip)# no max-forward-validation
Cisco 4700 Series Application Control Engine Appliance Security Configuration Guide
Configuring a SIP Parameter Map
3-119