32-24
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 32 Configuring SPAN and RSPAN
Configuring FSPAN and FRSPAN
Configuring FSPAN and FRSPAN
• FSPAN and FRSPAN Configuration Guidelines, page 32-24
• Configuring an FSPAN Session, page 32-25
• Configuring an FRSPAN Session, page 32-26

FSPAN and FRSPAN Configuration Guidelines

• You can attach ACLs to only one SPAN or RSPAN session at a time.
• When no FSPAN ACLs are attached, FSPAN is disabled, and all traffic is copied to the SPAN
destination ports.
• When at least one FSPAN ACL is attached, FSPAN is enabled.
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When you attach an empty FSPAN ACL to a SPAN session, it does not filter packets, and all
traffic is monitored.
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When you attach at least one FSPAN ACL that is not empty to a SPAN session, and you have
not attached one or more of the other FSPAN ACLs (for instance, you have attached an IPv4
ACL that is not empty, and have not attached IPv6 and MAC ACLs), FSPAN blocks the traffic
that would have been filtered by the unattached ACLs. Therefore, this traffic is not monitored.
• Port-based FSPAN sessions can be configured on a stack that includes Catalyst 3750 or Catalyst
3750-E switches as long as the session only includes Catalyst 3750-X ports as source ports. If the
session has any Catalyst 3750 or Catalyst 3750-E ports as source ports, the FSPAN ACL command
is rejected. If the session has FSPAN ACL configured, any commands including Catalyst 3750 or
Catalyst 3750-E ports as source ports are rejected. The Catalyst 3750 or Catalyst 3750-E ports can
be added as destination ports in an FSPAN session.
• VLAN-based FSPAN sessions cannot be configured on a stack that includes Catalyst 3750 switches.
• FSPAN ACLs cannot be applied to per-port-per-VLAN sessions. You can configure
per-port-per-VLAN sessions by first configuring a port-based session and then configuring specific
VLANs to the session. For example:
Switch (config)# monitor session session_number source interface interface-id
Switch (config)# monitor session session_number filter vlan vlan-id
Switch (config)# monitor session session_number filter ip access-group
(access-list-number | name}
Note Both the filter vlan and filter ip access-group commands cannot be configured at the same time.
Configuring one results in rejection of the other.
• EtherChannels are not supported in an FSPAN session.
• FSPAN ACLs with TCP flags or the log keyword are not supported.
• If you configure an IPv6 FSPAN ACL when the switch is running the advanced IP services feature
set but later run a different feature set, after rebooting the switch, the switch might lose the IPv6
FSPAN ACL configuration.
• IPv6 FSPAN ACLs are supported only on IPv6-enabled SDM templates. If you configure an IPv6
FSPAN ACL when running an IPv6 enabled SDM template, but later configure a non-IPv6 SDM
template and reboot the switch, you lose the IPv6 FSPAN ACL configuration.