Users Guide

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, IPv6 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
• ip access-list extended — create an extended ACL.
• permit — assign a permit lter for IP packets.
• permit udp — assign a permit lter for UDP packets.
seq arp (for Extended MAC ACLs)
Congure an egress lter with a sequence number that lters ARP packets meeting this criteria. This command is supported only on 12-
port GE line cards with SFP optics. For specications, refer to your line card documentation.
NOTE
: Only the options that have been newly introduced in Release 9.3(0.0) and Release 9.4(0.0) are described here. For a
complete description on all of the keywords and variables that are available with this command, refer the topic of this command
discussed earlier in this guide.
Syntax
seq sequence-number {deny | permit} arp {destination-mac-address mac-address-
mask | any} vlan vlan-id {ip-address | any | opcode code-number} [count [byte]]
[order] [log [interval minutes] [threshold-in-msgs [count]] [monitor]
To remove this lter, 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 terminated. with the seq, permit, or deny commands. You can enter a
threshold in the range of 1-100.
interval minutes (OPTIONAL) Enter the keyword interval followed by the time period in minutes at
which ACL logs must be generated. You can enter an interval in the range of 1-10 minutes.
monitor (OPTIONAL) Enter the keyword monitor when the rule is describing the trac 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 5 minutes. By default, ow-based monitoring is not
enabled.
284 Access Control Lists (ACL)