CLI Guide

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).
permit tcp
To pass TCP packets meeting the filter criteria, configure a filter.
Syntax
permit tcp {source mask | any | host ip-address} [bit]
[operator port [port]] {destination mask | any | host ip-
address} [bit] [dscp] [operator port [port]] [count [byte]]
[order] [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 permit tcp {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.
bit Enter a flag or combination of bits:
• ack: acknowledgement field
• fin: finish (no more data from the user)
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Access Control Lists (ACL)