Users Guide

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 (for IPv6 ACLs)
Configure a filter that drops IPv6 packets that match the filter criteria.
Syntax
deny {ipv6-protocol-number | icmp | ipv6 | tcp | udp} [count
[byte]] [dscp value] [order] [fragments] [log [interval minutes]
[threshold-in-msgs [count]] [monitor] [no-drop]
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 {ipv6-protocol-number | icmp | ipv6 | tcp | udp}
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.
no-drop Enter the keywords no-drop to match only the forwarded
packets.
Access Control Lists (ACL) 400