The IDSM-2 technically has 8 ports, but only 4 are used.
In traditional Cat OS these 4 ports are:
port 1 - this is the TCP Reset port, I would suggest not modifying the configuration on this port
port 2 - this is the management port, you will need to place this in the correct vlan for the subnet for the ip address you will be assigning to the IDSM-2 (use the setup command on the IDSM-2 to assign it's ip address) use the "set vlan /2" command to do this
ports 3-6 - these ports are disabled and should not be enabled by the user. The IDSM-2 is built off a base card that is used by a few other service modules. These other service modules needed these ports. Since the IDSM-2 does not need them (and in fact can not function with them) they have been disabled.
ports 7 and 8 - these are the monitoring ports, You can configure them as either span destination ports or VACL Capture ports. In most scenarios users need only configure one of these ports. It is only in rare cases that a user will need to configure both port 7 and 8 for monitoring.
Refer to the User's Guide for more information:
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/csids/csids10/hwguide/hwchap9.htm#589679
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/csids/csids10/hwguide/hwchap9.htm#589909
If running IOS on the switch instead of the traditional Cat OS:
port 1 - NOT configurable in IOS - it is still used as the TCP Reset port, but the user is not allowed to modify or even see the configuration for the port
port 2 - management port - configured as the "intrusion-detection module management-port" use this command to place the port into the correct vlan for the ip address being assigned to the IDSM-2.
ports 3-6 - disabled, and are not even viewable in Native IOS configurations
ports 7 and 8 - monitoring ports - they are referred to as data-ports 1 and 2. data-port 1 is port 7, and data-port 2 is port 8.
You can configure them as either span destination ports using the "monitor session destination intrusion-detection-module data-port <1or2>" command; or VACL Capture ports using the "intrusion-detection module data-port <1or2> capture" command or the . In most scenarios users need only configure one of these ports. It is only in rare cases that a user will need to configure both port 7 and 8 for monitoring.
Refer to the User's Guide for more information:
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/csids/csids10/hwguide/hwchap9.htm#589679
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/csids/csids10/hwguide/hwchap9.htm#589909
