Administrator Guide
Version Description
9.3.0.0 Added support for logging of ACLs on the S4810, S4820T, Z9000, and MXL
10/40GbE Switch IO Module platforms.
Usage
Information
When the configured maximum threshold is exceeded, generation of logs is stopped. When the interval at
which ACL logs are configured to be recorded expires, the 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 reenabled for this new interval.
If ACL logging is stopped because the configured threshold is exceeded, it is reenabled after the logging
interval period elapses. ACL logging is supported for standard and extended IPv4 ACLs, standard and
extended IPv6 ACLs, and standard and extended 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).
seq (for IP ACLs)
Assign a sequence number to a deny or permit filter in an extended IP access list while creating the filter.
Syntax
seq sequence-number {deny | permit} {ip-protocol-number | icmp | ip | tcp |
udp} {source mask | any | host ip-address} {destination mask | any | host
ip-address} [operator port [port]] [ttl operator] [count [byte]] [dscp
value] [order] [fragments] [log [interval minutes] [threshold-in-msgs
[count]] [monitor]
Parameters
ttl Enter the keyword ttl to permit or deny a packet based on the time to live value.
The range is from 1 to 255.
operator
Enter one of the following logical operand:
● eq(equal to) — matches packets that contain a ttl value that is equal to the
specified ttl value.
● neq(not equal to) — matches packets that contain a ttl value that is not equal
to the specified ttl value.
● gt(greater than) — matches packets that contain a ttl value that is greater
than the specified ttl value.
● lt (less than) — matches packets that contain a ttl value that is less than the
specified ttl value.
● range(inclusive range of values) — matches packets that contain a ttl value
that falls between the specified range of ttl values.
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 interval range is from 1 to 10 minutes.
Access Control Lists (ACL) 295