Users Guide

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 IP ACLs)
To drop all or specific internet control message protocol (ICMP) messages, configure a filter.
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 mask | any | host ip-address} {destination mask
| any | host ip-address} [dscp] [message-type] [count [byte]]
[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 if you know the filter’s sequence
number.
• Use the no deny icmp {source mask | any | host ip-address}
{destination mask | any | host ip-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
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
time 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.
Defaults
By default, 10 ACL logs are generated if you do not specify the threshold explicitly.
Access Control Lists (ACL) 357