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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).
permit udp
To pass UDP packets meeting the filter criteria, configure a filter.
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 filter, you have two choices:
● Use the no seq sequence-number command if you know the filter’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.
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 and then enter the IP address to specify a host IP
address.
dscp Enter the keyword dscp to deny a packet based on the DSCP value. The range is
from 0 to 63.
operator (OPTIONAL) Enter one of the following logical operand:
● eq = equal to
● neq = not equal to
● gt = greater than
● lt = less than
● range = inclusive range of ports (you must specify two ports for the port
parameter)
port port Enter the application layer port number. Enter two port numbers if you are using
the range logical operand. The range is 0 to 65535.
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-order numbers have a higher priority). If you do not use the keyword
order, the ACLs have the lowest order by default (255).
fragments Enter the keyword fragments to use ACLs to control packet fragments.
threshold-in
msgs count
(OPTIONAL) Enter the threshold-in-msgs keyword followed by a value to
indicate the maximum number of ACL logs that can be generated, exceeding
212 Access Control Lists (ACL)