Administrator Guide

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 — configure a filter to drop packets.
• permit — configure a filter to forward packets.
deny tcp (for Extended IP ACLs)
Configure a filter that drops transmission control protocol (TCP) packets meeting the filter criteria.
Syntax
deny tcp {source mask | any | host ip-address} [bit] [operator port [port]]
{destination mask | any | host ip-address} [ttl operator] [dscp] [bit]
[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 deny tcp {source mask | any | host ip-address} {destination mask |
any | host ip-address} command.
Parameters
ttl Enter the keyword ttl to deny a packet based on the time to live value. The range is
from 1 to 255.
operator Enter one of the following logical operand:
• eq(equal to) — matches packets that contain a ttl value that is equal to the specified
ttl value.
• neq(not equal to) — matches packets that contain a ttl value that is not equal to the
specified ttl value.
•
gt(greater than) — matches packets that contain a ttl value that is greater than the
specified ttl value.
• lt (less than) — matches packets that contain a ttl value that is less than the
specified ttl value.
• range(inclusive range of values) — matches packets that contain a ttl value that
falls between the specified range of ttl values.
log (OPTIONAL) Enter the keyword log to enable the triggering of ACL log messages.
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 which the generation
of ACL logs is terminated. with the seq, permit, or deny commands. The threshold range
is from 1 to 100.
interval minutes (OPTIONAL) Enter the keyword interval followed by the time period in minutes at
which ACL logs must be generated. The interval range is from 1 to 10 minutes.
monitor (OPTIONAL) Enter the keyword monitor when the rule is describing the traffic that you
want to monitor and the ACL in which you are creating the rule is applied to the
monitored interface.
Defaults
By default, 10 ACL logs are generated if you do not specify the threshold explicitly.
The default frequency at which ACL logs are generated is five minutes. By default, flow-based monitoring is not
enabled.
Command Modes CONFIGURATION-EXTENDED-ACCESS-LIST
Command History
This guide is platform-specific. For command information about other platforms, see the relevant Dell EMC
Networking OS Command Line Reference Guide.
Access Control Lists (ACL) 275