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fragments Enter the keyword fragments to use ACLs to control packet fragments.
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.
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 CONFIGURATION-IP ACCESS-LIST-STANDARD
Supported Modes Full–Switch
Command
History
Version Description
9.9(0.0) Introduced on the FN IOM.
9.4(0.0) Added support for flow-based monitoring on the MXL 10/40GbE Switch IO Module
platform.
9.3(0.0) Added support for logging of ACLs on the MXL 10/40GbE Switch IO Module
platform.
8.3.16.1 Introduced on the MXL 10/40GbE Switch IO Module.
Usage
Information
The order option is relevant in the context of the Policy QoS feature only. The following applies:
● The seq sequence-number command is applicable only in an ACL group.
● The order option works across ACL groups that have been applied on an interface via the QoS policy
framework.
● The order option takes precedence over seq sequence-number.
● If sequence-number is not configured, the rules with the same order value are ordered according to
their configuration order.
● If sequence-number is configured, the sequence-number is used as a tie breaker for rules with the
same order.
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.
You can activate flow-based monitoring for a monitoring session by entering the flow-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
deny — configures a filter to drop packets.
permit — configures a filter to forward packets.
seq — assigns a sequence number to a deny or permit filter in an IP access list while creating the filter.
194 Access Control Lists (ACL)