Dell S3100 EMC Command Line Reference Guide for the Series 9.14.2.1 - Page 308

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). deny icmp (for Extended IP ACLs) To drop all or specific internet control message protocol (ICMP) messages, configure a filter. NOTE: Only the options that have been newly introduced in Release 9.3(0.0) and Release 9.4(0.0) are described here. For a complete description on all of the keywords and variables that are available with this command, refer the topic of this command discussed earlier in this guide. Syntax deny icmp {source mask | any | host ip-address} {destination mask | any | host ip-address} [ttl operator] [dscp] [message-type] [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 icmp {source mask | any | host ip-address} {destination mask | any | host ip-address} command. Parameters ttl operator Enter the keyword ttl to deny a packet based on the time to live value. The range is from 1 to 255. 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. 308 Access Control Lists (ACL)