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).
The order option is relevant in the context of the Policy QoS feature only. For more information, refer to the
Quality of Service chapter of the Dell Networking OS Configuration Guide.
The monitor option is relevant in the context of flow-based monitoring only. For more information, refer to the
Port Monitoring.
When you use the log option, the CP processor logs details the packets that match. Depending on how many
packets match the log entry and at what rate, the CP may become busy as it has to log these packets’ details.
You cannot include IP, TCP or UDP (Layer 3) filters in an ACL configured with ARP or Ether-type (Layer 2) filters.
Apply Layer 2 ACLs (ARP and Ether-type) to Layer 2 interfaces only.
NOTE
: When ACL logging and byte counters are configured simultaneously, byte counters may display
an incorrect value. Configure packet counters with logging instead.
deny icmp
To drop all or specific internet control message protocol (ICMP) messages, configure a filter.
Syntax
deny icmp {source mask | any | host ip-address} {destination mask | any | host
ip-address} [dscp] [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 deny icmp {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.
Access Control Lists (ACL) 209