Service Manual

Usage Information
When the configured maximum threshold is exceeded, generation of logs is stopped.
When the interval at which ACL logs are configured to be recorded expires, the
subsequent, fresh interval timer is started and the packet count for that new interval
commences from zero. If ACL logging was stopped previously because the configured
threshold is exceeded, it is re-enabled for this new interval.
If ACL logging is stopped because the configured threshold is exceeded, it is re-
enabled after the logging interval period elapses. ACL logging is supported for standard
and extended IPv4 ACLs, standard and extended IPv6 ACLs, and standard and extended
MAC ACLs. You can configure ACL logging only on ACLs that are applied to ingress
interfaces; you cannot enable logging for ACLs that are associated with egress
interfaces.
You can activate flow-based monitoring for a monitoring session by entering theflow-
based enable command in the Monitor Session mode. When you enable this
capability, traffic with particular flows that are traversing through the ingress and egress
interfaces are examined and, appropriate ACLs can be applied in both the ingress and
egress direction. Flow-based monitoring conserves bandwidth by monitoring only
specified traffic instead all traffic on the interface. This feature is particularly useful
when looking for malicious traffic. It is available for Layer 2 and Layer 3 ingress and
egress traffic. You may specify traffic using standard or extended access-lists. This
mechanism copies all incoming or outgoing packets on one port and forwards (mirrors)
them to another port. The source port is the monitored port (MD) and the destination
port is the monitoring port (MG).
Related
Commands
• ip access-list extended — create an extended ACL.
• permit tcp — assign a permit filter for TCP packets.
• permit udp — assign a permit filter for UDP packets.
permit (for Standard MAC ACLs)
To forward packets from a specific source MAC address, configure a filter.
Syntax
permit {any | mac-source-address [mac-source-address-mask]} [count
[byte]] | [log [interval minutes] [threshold-in-msgs [count]]
[monitor]
To remove this filter, you have two choices:
• Use the no seq sequence-number command if you know the filter’s sequence
number.
• Use the no permit {any | mac-source-address mac-source-address-
mask} command.
Access Control Lists (ACL) 374