Users Guide
Version Description
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.
9.5(0.1) Introduced on the Z9500.
9.4(0.0) Added support for ow-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 congured maximum threshold is exceeded, generation of logs is stopped. When the interval at which 
ACL logs are congured 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 congured 
threshold is exceeded, it is re-enabled for this new interval.
If ACL logging is stopped because the congured 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 congure 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 ow-based monitoring for a monitoring session by entering the ow-based enable command in 
the Monitor Session mode. When you enable this capability, trac with particular ows 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 specied trac instead all trac 
on the interface. This feature is particularly useful when looking for malicious trac. It is available for Layer 2 and 
Layer 3 ingress and egress trac. You may specify trac 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 udp (for Extended IP ACLs)
To drop user datagram protocol (UDP) packets meeting the lter criteria, congure a lter.
Syntax
deny udp {source mask | any | host ip-address} [operator port [port]] 
{destination mask | any | host ip-address} [dscp] [operator port [port]] [count 
[byte]] [order] [fragments] [log [interval minutes] [threshold-in-msgs [count]]
To remove this lter, you have two choices:
• Use the no seq sequence-number command if you know the lter’s sequence number.
•
Use the no deny udp {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.
Access Control Lists (ACL) 329










