Chapter 20
Configuring SPAN
Configuring Local SPAN
These sections contain this configuration information:
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SPAN Configuration Guidelines
Follow these guidelines when configuring SPAN:
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Creating a Local SPAN Session
Beginning in privileged EXEC mode, follow these steps to create a SPAN session and specify the source
(monitored) ports or VLANs and the destination (monitoring) ports:
Command
Step 1
configure terminal
Step 2
no monitor session {session_number | all |
local | remote}
OL-19808-01
SPAN Configuration Guidelines, page 20-7
Creating a Local SPAN Session, page 20-7
Creating a Local SPAN Session and Configuring Incoming Traffic, page 20-10
Specifying VLANs to Filter, page 20-11
You can configure one SPAN source session on a switch.
For SPAN sources, you can monitor traffic for a single port or VLAN or a series or range of ports
or VLANs for each session. You cannot mix source ports and source VLANs within a single SPAN
session.
The destination port cannot be a source port; a source port cannot be a destination port.
When you configure a switch port as a SPAN destination port, it is no longer a normal switch port;
only monitored traffic passes through the SPAN destination port.
Entering SPAN configuration commands does not remove previously configured SPAN parameters.
You must enter the no monitor session {session_number | all | local | remote} global configuration
command to delete configured SPAN parameters.
For local SPAN, outgoing packets through the SPAN destination port carry the original
encapsulation headers—untagged or IEEE 802.1Q—if the encapsulation replicate keywords are
specified. If the keywords are not specified, the packets are sent in native form.
You can configure a disabled port to be a source or destination port, but the SPAN function does not
start until the destination port and at least one source port or source VLAN are enabled.
You can limit SPAN traffic to specific VLANs by using the filter vlan keyword. If a trunk port is
being monitored, only traffic on the VLANs specified with this keyword is monitored. By default,
all VLANs are monitored on a trunk port.
You cannot mix source VLANs and filter VLANs within a single SPAN session.
Purpose
Enter global configuration mode.
Remove any existing SPAN configuration for the session.
For session_number, the range is 1 to 66.
Specify all to remove all SPAN sessions, local to remove all local
sessions, or remote to remove all remote SPAN sessions.
Catalyst 2360 Switch Software Configuration Guide
Configuring SPAN
20-7