CLI Guide

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).
Related
Commands
deny – assigns a filter to deny IP traffic.
deny udp – assigns a filter to deny UDP traffic.
deny icmp (for Extended IPv6 ACLs)
Configure a filter to drop all or specific ICMP messages.
Syntax
deny icmp {source address mask | any | host ipv6-address}
{destination address | any | host ipv6-address} [count [byte]]
| [log [interval minutes] [threshold-in-msgs [count]] [monitor]
To remove this filter, you have two choices:
• Use the no seq sequence-number command syntax if you know the filter’s
sequence number
• Use the no deny icmp {source address mask | any | host ipv6-
address} {destination address | any | host ipv6-address}
command
Parameters `
source Enter the IPv6 address of the network or host from which
the packets were sent.
mask Enter a network mask in /prefix format (/x) or A.B.C.D. The
mask, when specified in A.B.C.D format, may be either
contiguous or non-contiguous.
any Enter the keyword any to specify that all routes are subject
to the filter.
Access Control Lists (ACL)
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