Administrator Guide

Usage Information
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gure a lter to drop packets.
• permit — congure a lter to forward packets.
seq (for IPv6 ACLs)
Assign a sequence number to a deny or permit the lter in an IPv6 access list while creating the lter.
Syntax
seq sequence-number {deny | permit} {ipv6-protocol-number | icmp | ip | tcp |
udp} {source address mask | any | host ipv6-address} {destination address | any
| host ipv6-address} [operator port [portnumber ]] [count [byte]] [log
[interval minutes] [threshold-in-msgs [count]] [monitor]
To delete a lter, use the no seq sequence-number command.
Parameters
sequence-number Enter a number from 0 to 4294967290.
deny Enter the keyword deny to congure a lter to drop packets meeting this condition.
permit Enter the keyword permit to congure a lter to forward packets meeting this criteria.
ipv6-protocol-
number
Enter a number to lter based on the protocol identied in the IPv6 protocol header.
icmp Enter the keyword icmp to congure an ICMP access list lter.
ip Enter the keyword ip to congure a generic IP access list. The keyword ip species that
the access list permits all IP protocols.
tcp Enter the keyword tcp to congure a TCP access list lter.
udp Enter the keyword udp to congure a UDP access list lter.
source Enter an IP address in dotted decimal format of the network from which the packet was
received.
mask (OPTIONAL) Enter a network mask in /prex format (/x) .
Access Control Lists (ACL) 305