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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 21 Configuring SPAN and RSPAN Configuring SPAN

Specifying VLANs to Filter

Beginn ing in p ri vil eged EXEC mode , follow t hese ste ps to lim it SPAN source traff ic to specific VLANs:
To monitor all VLANs on the trunk port, use the no monitor session session_number filter global
configurati on comm a nd.
This example sho ws how to clear any existing configuration on SPAN session 2, configure SPAN session
2 to monitor traffi c received on trunk port 4, and sen d traffic for onl y VLANs 1 throu gh 5 and 9 to
destinati on port 8.
Switch(config)# no monitor session 2
Switch(config)# monitor session 2 source interface gigabitethernet0/4 rx
Switch(config)# monitor session 2 filter vlan 1 - 5 , 9
Switch(config)# monitor session 2 destination interface gigabitethernet0/8
Switch(config)# end
Command Purpose
Step 1 configure terminal Enter glob al co nfiguration mo de.
Step 2 no monitor session {session_number | all |
local | remote}Clear a ny existing SPAN configura tion f or the se ssion .
For session_number, specify 1 or 2.
Specify all to remove all SPAN session s, local to remove all local
sessions, or remote to remove all remote SPAN sessions.
Step 3 monitor s ession session_number source
interface in terface-id rx Specify the characteristics of the source port ( monitored port) and
SPAN session.
For session_number, specify 1 or 2.
For interface-id, specify the source port to monitor. The interface
specified must al rea dy be c onfigure d as a trun k p ort.
Step 4 monitor session session_number f ilter vlan
vlan -id [, | -]Limit the SPAN source traffic to specific VLANs.
For session_number, specify 1 or 2.
For vlan-id, the ra nge is 1 to 4094; do not enter leading ze ros.
(Optional) Use a comma (,) to specify a series of VLANs or use a
hyphen ( -) to specify a range of VLANs. Enter a space after the
comm a; enter a space befo re and aft er the hyphe n.
Step 5 monitor s ession session_number
destination interface interface-id Specify the characteristics of the destination port (monitoring port)
and SPAN session.
For session_number, specify 1 or 2.
For interface-id, specif y th e d estinat ion p o rt. Va lid inter f a ces in cl ude
physical int erfaces.
Step 6 end Return to privileged EXEC mode.
Step 7 show monitor [session session_number] Verify your entries.
Step 8 copy running-config startup-config (Optional) Save your entries in the configuration file.