Users Guide

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).
deny icmp (for Extended IPv6 ACLs)
Configure a filter to drop all or specific ICMP messages.
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
deny icmp {source address mask | any | host ipv6-address}
{destination address | any | host ipv6-address} [message-type]
[count [byte]] | [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 deny icmp {source address mask | any | host ipv6-
address} {destination address | any | host ipv6-address}
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
Access Control Lists (ACL) 398