Users Guide

When the interval at which ACL logs are congured 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 congured threshold is exceeded, it is re-enabled for this new interval.
If ACL logging is stopped because the congured threshold is exceeded, it is re-enabled after the logging interval
period elapses. ACL logging is supported for standard and extended IPv4 ACLs, Pv6 ACLs, and MAC ACLs. You
can congure 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 ow-based monitoring for a monitoring session by entering the flow-based enable
command in the Monitor Session mode. When you enable this capability, trac with particular ows 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 specied trac
instead all trac on the interface. This feature is particularly useful when looking for malicious trac. It is available
for Layer 2 and Layer 3 ingress and egress trac. You may specify trac 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
deny — congures a MAC ACL lter to drop packets.
seq —congure a MAC ACL lter with a specied sequence number.
seq
To a deny or permit lter in a MAC access list while creating the lter, assign a sequence number.
Syntax
seq sequence-number {deny | permit} {any | mac-source-address [mac-source-
address-mask]} [count [byte]] [log [interval minutes] [threshold-in-msgs
[count]] [monitor]
To remove this lter, use the no seq sequence-number command.
Parameters
sequence-number Enter a number from 0 to 65535.
deny Enter the keyword deny to congure a lter to drop packets meeting this condition.
permit Enter the keyword permit to congure a lter to forward packets meeting this criteria.
any Enter the keyword any to lter all packets.
mac-source-
address
Enter a MAC address in nn:nn:nn:nn:nn:nn format.
mac-source-
address-mask
(OPTIONAL) Specify which bits in the MAC address must match. If no mask is specied,
a mask of 00:00:00:00:00:00 is applied (in other words, the lter allows only MAC
addresses that match).
count (OPTIONAL) Enter the keyword count to count packets the lter processes.
byte (OPTIONAL) Enter the keyword byte to count bytes the lter processes.
log (OPTIONAL) Enter the keyword log to enable the triggering of ACL log messages.
threshold-in msgs
count
(OPTIONAL) Enter the threshold-in-msgs keyword followed by a value to indicate
the maximum number of ACL logs that can be generated, exceeding which the generation
190 Access Control Lists (ACL)