Command Line Reference Guide

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.
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).
permit (for IPv6 ACLs)
To configure a filter that matches the filter criteria, select an IPv6 protocol number, ICMP, IPv6, TCP, or
UDP.
Syntax
permit {ipv6-protocol-number | icmp | ipv6 | tcp | udp} [count
[byte]] [dscp value] [order] [fragments] [log [interval
minutes] [threshold-in-msgs [count]] [monitor]
To remove this filter, you have two choices:
• Use the no seq sequence-number command syntax if you know the filter’s
sequence number
• Use the no permit {ipv6-protocol-number | icmp | ipv6 | tcp |
udp}
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 terminated 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.
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Access Control Lists (ACL)