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logs is terminated. You can enter a threshold in the range of 1-100. By default, 10 ACL logs are generated if you do not
specify the threshold explicitly.
CONFIG-STD-NACL mode
seq sequence-number {deny | permit} {source [mask] | any | host ip-address} [log
[threshold-in-msgs count] ]
2. Specify the interval in minutes at which ACL logs must be generated. You can enter an interval in the range of 1-10 minutes.
The default frequency at which ACL logs are generated is 5 minutes. If ACL logging is stopped because the configured
threshold has exceeded, it is re-enabled after the logging interval period elapses. ACL logging is supported for standard
and extended IPv4 ACLs, IPv6 ACLs, and standard and extended MAC ACLs. Configure ACL logging only on ACLs that are
applied to ingress interfaces; you cannot enable logging for ACLs that are associated with egress interfaces.
CONFIG-STD-NACL mode
seq sequence-number {deny | permit} {source [mask] | any | host ip-address} [log
[interval minutes]]
Flow-Based Monitoring Support for ACLs
Flow-based monitoring conserves bandwidth by monitoring only the specified traffic instead of all traffic on the interface. It is
available for Layer 2 and Layer 3 ingress traffic. You can specify traffic using standard or extended access-lists. This feature
copies all incoming 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).
The port mirroring application maintains and performs all the monitoring operations on the chassis. ACL information is sent to
the ACL manager, which in turn notifies the ACL agent to add entries in the CAM area. Duplicate entries in the ACL are not
saved.
When a packet arrives at a port that is being monitored, the packet is validated against the configured ACL rules. If the packet
matches an ACL rule, the system examines the corresponding flow processor to perform the action specified for that port. If the
mirroring action is set in the flow processor entry, the destination port details, to which the mirrored information must be sent,
are sent to the destination port.
When a stack unit is reset or a stack unit undergoes a failure, the ACL agent registers with the port mirroring application. The
port mirroring utility downloads the monitoring configuration to the ACL agent. The interface manager notifies the port mirroring
application about the removal of an interface when an ACL entry associated with that interface to is deleted.
Behavior of Flow-Based Monitoring
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 interfaces
are examined, and appropriate ACLs can be applied in the ingress direction. By default, flow-based monitoring is not enabled.
You must specify the monitor option with the permit, deny, or seq command for ACLs that are assigned to the source
or the monitored port (MD) to enable the evaluation and replication of traffic that is traversing to the destination port. Enter
the keyword monitor with the seq, permit, or deny command for the ACL rules to allow or drop IPv4, IPv6, ARP, UDP,
EtherType, ICMP, and TCP packets. The ACL rule describes the traffic that you want to monitor, and the ACL in which you are
creating the rule will be applied to the monitored interface. Flow monitoring is supported for standard and extended IPv4 ACLs,
standard and extended IPv6 ACLs, and standard and extended MAC ACLs.
CONFIG-STD-NACL mode
seq sequence-number {deny | permit} {source [mask] | any | host ip-address} [count [byte]]
[monitor]
If the number of monitoring sessions increases, inter-process communication (IPC) bandwidth utilization will be high. The ACL
manager might require a large bandwidth when you assign an ACL, with many entries, to an interface.
The ACL agent module saves monitoring details in its local database and also in the CAM region to monitor packets that match
the specified criterion. The ACL agent maintains data on the source port, the destination port, and the endpoint to which the
packet must be forwarded when a match occurs with the ACL entry.
If you configure the flow-based enable command and do not apply an ACL on the source port or the monitored port, both
flow-based monitoring and port mirroring do not function. Flow-based monitoring is supported only for ingress traffic and not
for egress packets.
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Access Control Lists (ACLs)