Administrator Guide

Version Description
9.12(0.0) Introduced the ttl parameter.
9.10(0.1) Introduced on the S6010-ON and S4048T-ON.
9.10(0.0) Introduced on the S3148.
9.10(0.0) Introduced on the S6100.
9.8(2.0) Introduced on the S3100 series.
9.8(1.0) Introduced on the Z9100–ON.
9.8(0.0P5) Introduced on the S4048-ON.
9.8(0.0P2) Introduced on the S3048-ON.
9.7(0.0) Introduced on the S6000–ON.
9.4(0.0) Added support for flow-based monitoring on the S4810, S4820T, S6000, and Z9000
platforms.
9.3(0.0) Added support for logging of ACLs on the S4810, S4820T, and Z9000 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 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 theflow-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).
permit udp (for Extended IP ACLs)
To pass UDP packets meeting the filter criteria, configure a filter.
Syntax
permit udp {source mask | any | host ip-address} [operator port [port]]
{destination mask | any | host ip-address} [ttl operator] [dscp] [operator port
[port]] [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 permit udp {source mask | any | host ip-address} {destination mask |
any | host ip-address command.
Parameters
ttl Enter the keyword ttl to permit 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.
288 Access Control Lists (ACL)