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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
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Chapter 23 Configuring Network Security
Configuring the Cisco IOS Firewall Feature Set
Security server support
Network address translation
Neighbor router authentication
Event logging
User authentication and authorization
Note Catalyst 6500 series switches support the Intrusion Detection System Module (IDSM)
(WS-X6381-IDS). Catalyst 6500 series switches do not support the Cisco IOS firewall IDS feature,
which is configured with the ip audit command.
Firewall Configuration Guidelines and Restrictions
Follow these guidelines and restrictions when configuring the Cisco IOS firewall features:

Restrictions

On other platforms, if you enter the ip inspect command on a port, CBAC modifies ACLs on other
ports to permit the inspected traffic to flow through the network device. On Catalyst 6500 series
switches, you must enter the mls ip inspect commands to permit traffic through any ACLs that
would deny the traffic through other ports. See the “Configuring CBAC on Catalyst 6500 Series
Switches” section on page 23-7.
With Supervisor Engine 2 and PFC2, reflexive ACLs and CBAC have conflicting flow mask
requirements. When you configure CBAC on a switch with Supervisor Engine 2 and PFC2, reflexive
ACLs are processed in software on the MSFC2.
CBAC is incompatible with VACLs. You can configure both CBAC and VACLs on the switch but
not in the same subnet (VLAN) or on the same interface.
Note The Intrusion Detection System Module (IDSM) uses VACLs to select traffic. To use the
IDSM in a subnet where CBAC is configured, enter the mls ip ids acl_name interface
command, where acl_name is configured to select traffic for the IDSM.
Guidelines
To inspect Microsoft NetMeeting (2.0 or greater) traffic, turn on both h323 and tcp inspection.
To inspect web traffic, turn on tcp inspection. To avoid reduced performance, do not turn on http
inspection to block Java.
You can configure CBAC on physical ports configured as Layer 3 interfaces and on VLAN
interfaces.
QoS and CBAC do not interact or interfere with each other.