ACL logging matched packets

Using the log or log-input keywords at the end of an Access-List (ACL) permit or deny statement will cause informational logging of packets that match that particular statement.

On Cisco IOS , The Syslog message is generated for the first packet that matches a flow. Subsequently, a message is generated at five minute intervals which includes the number of matched packets in the prior five minute interval. This behavior can be different for different platforms and/or operating systems.