Service Manual

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 the flow-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
ip access-list standard — configures a standard ACL.
permit — configures a permit filter.
deny (for Extended IP ACLs)
Configure a filter that drops IP packets meeting the filter criteria.
Syntax
deny {ip | ip-protocol-number} {source mask | any | host ip-address}
{destination mask | any | host ip-address} [count [byte]] [dscp value] [order]
[monitor] [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 deny {ip | ip-protocol-number} {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.
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.
host ip-address Enter the keyword host then the IP address to specify a host IP address.
destination Enter the IP address of the network or host to which the packets are sent.
count (OPTIONAL) Enter the keyword count to count packets processed by the filter.
byte (OPTIONAL) Enter the keyword byte to count bytes processed by the filter.
order (OPTIONAL) Enter the keyword order to specify the QoS priority for the ACL entry.
The range is from 0 to 254 (where 0 is the highest priority and 254 is the lowest; lower
Access Control Lists (ACL) 199