Users Guide

Usage Information
The order option is relevant in the context of the Policy QoS feature only. The following applies:
• The seq sequence-number command is applicable only in an ACL group.
• The order option works across ACL groups that have been applied on an interface via the QoS policy
framework.
• The order option takes precedence over seq sequence-number.
• If sequence-number is not congured, the rules with the same order value are ordered according to their
conguration order.
• If sequence-number is congured, the sequence-number is used as a tie breaker for rules with the same
order.
If you congure the sequence-number, the sequence-number is used as a tie breaker for rules with the
same order.
When the congured maximum threshold is exceeded, generation of logs is stopped. When the interval at which
ACL logs are congured 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 congured
threshold is exceeded, it is re-enabled for this new interval.
If ACL logging is stopped because the congured 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 congure 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 flow-based enable
command in the Monitor Session mode. When you enable this capability, trac 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 specied trac
instead all trac on the interface. This feature is particularly useful when looking for malicious trac. It is available
for Layer 2 and Layer 3 ingress and egress trac. You may specify trac 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).
Related Commands
deny — Congures a lter to drop packets.
permit — Congures a lter to forward packets.
permit udp
To pass UDP packets meeting the lter criteria, congure a lter.
Syntax
permit udp {source mask | any | host ip-address} [operator port [port]]
{destination mask | any | host ip-address} [dscp] [operator port [port]] [count
[byte]] [order] [fragments] [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 permit udp {source mask | any | host ip-address} {destination mask |
any | host ip-address command.
Parameters
source Enter the IP address of the network or host from which the packets were sent.
252 Access Control Lists (ACL)