Cisco Systems 2950, 2955 Creating a SPAN Session and Enabling Ingress Traffic

24-9
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 24 Configuring SPAN and RSPAN
Configuring SPAN
Switch(config)# no monitor session 1
Switch(config)# monitor session 1 source interface fastethernet0/10/17
Switch(config)# monitor session 1 destination interface fastethernet0/80/18
encapsulation dot1q
Switch(config)# end
Creating a SPAN Session and Enabling Ingress Traffic
Beginning in privileged EXEC mode, follow these steps to create a SPAN session, to specify the source
and destination ports, and to enable ingress traffic on the destination port for a network security device
(such as a Cisco IDS Sensor Appliance):
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 no monitor session {session_number | all |
local | remote}
Clear any existing SPAN configuration for the session.
For session_number, specify 1.
Specify all to remove all SPAN sessions, local to remove all local
sessions, or remote to remove all remote SPAN sessions.
Step 3 monitor session session_number source
interface interface-id [, | -] [both | rx | tx]
Specify the SPAN session and the source port (monitored port).
For session_number, specify 1.
For interface-id, specify the source port to monitor. Valid interfaces
include physical interfaces and port-channel logical interfaces
(port-channel port-channel-number).
(Optional) [, | -] Specify a series or range of interfaces. Enter a space
before and after the comma; enter a space before and after the
hyphen.
(Optional) Specify the direction of traffic to monitor. If you do not
specify a traffic direction, the source interface sends both sent and
received traffic.
• both—Monitor both received and sent traffic.
• rx—Monitor received traffic.
• tx—Monitor sent traffic.
Step 4 monitor session session_number
destination interface interface-id
[encapsulation {dot1q}] [ingress vlan
vlan id]
Specify the SPAN session, the destination port (monitoring port), the
packet encapsulation, and the ingress VLAN.
For session_number, specify 1.
For interface-id, specify the destination port. Valid interfaces include
physical interfaces.
(Optional) Specify the IEEE 802.1Q encapsulation header for
outgoing packets. If not specified, packets are sent in native form.
(Optional) Enter ingress vlan vlan id to enable ingress forwarding
and specify a default VLAN
Step 5 end Return to privileged EXEC mode.
Step 6 show monitor [session session_number]Verify your entries.
Step 7 copy running-config startup-config (Optional) Save your entries in the configuration file.