IPv4 Access Control Lists (ACLs)

Enable ACL “Deny” Logging

Enable ACL “Deny” Logging

ACL logging enables the switch to generate a message when IP traffic meets the criteria for a match with an ACE that results in an explicit “deny” action. You can use ACL logging to help:

Test your network to ensure that your ACL configuration is detecting and denying the IP traffic you do not want forwarded

Receive notification when the switch detects attempts to forward IP traffic you have designed your ACLs to reject (deny)

The switch sends ACL messages to Syslog and optionally to the current console, Telnet, or SSH session. You can use logging < > to configure up to six Syslog server destinations.

Requirements for Using ACL Logging

The switch configuration must include an ACL (1) assigned to a port or trunk and (2) containing an ACE configured with the deny action and the log option.

For ACL logging to a Syslog server:

The server must be accessible to the switch and identified in the running configuration.

The logging facility must be enabled for Syslog.

Debug must be configured to:

support ACL messages

send debug messages to the desired debug destination

These requirements are described in more detail under “Enabling ACL

Logging on the Switch” on page 9-98.

9-96