Administrator Guide

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
permit (for Standard IPv6 ACLs) – configures a filter to forward IPv6 packets.
seq (for IPv6 ACLs)
Assign a sequence number to a deny or permit the filter in an IPv6 access list while creating the filter.
C9000 Series
Syntax
seq sequence-number {deny | permit} {ipv6-protocol-number | icmp | ip | tcp |
udp} {source address mask | any | host ipv6-address} {destination address | any
| host ipv6-address} [operator port [port]] [count [byte]] [log [interval
minutes] [threshold-in-msgs [count]] [monitor]
To delete a filter, use the no seq sequence-number command.
Parameters
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
of ACL logs is terminate with the seq, permit, or deny commands. The threshold range
is from 1 to 100.
interval minutes (OPTIONAL) Enter the keyword interval followed by the time period in minutes at
which ACL logs must be generated. The interval range is from 1 to 10 minutes.
monitor (OPTIONAL) Enter the keyword monitor when the rule is describing the traffic that you
want to monitor and the ACL in which you are creating the rule is applied to the
monitored interface.
Defaults
By default, 10 ACL logs are generated if you do not specify the threshold explicitly.
The default frequency at which ACL logs are generated is five minutes. By default, flow-based monitoring is not
enabled.
Command Modes ACCESS-LIST
Command History
Version Description
9.9(0.0) Introduced on the C9010.
9.5(0.1) Introduced on the Z9500.
9.4(0.0) Added support for flow-based monitoring on the S4810, S4820T, S6000, and Z9000
platforms.
9.3(0.0) Added support for logging of ACLs on the S4810, S4820T, and Z9000 platforms.
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, IPv6 ACLs, and 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.
IPv6 Access Control Lists (IPv6 ACLs) 915