Allied Telesis AT-S62 - Manual (Page 226)

Chapter 14: Classifiers
Section II: Advanced Operations 226
❑ The Protocol variable must be left blank or set to IP.
❑ The IP Protocol variable must be left blank or set to UDP.
❑ A classifier cannot contain criteria for both TCP and UDP ports.
You may specify only one in a classifier.
TCP Flags
A traffic flow can be based on the following TCP flags:
❑ URG - Urgent
❑ ACK - Acknowledgement
❑ RST - Reset
❑ PSH - Push
❑ SYN - Synchronization
❑ FIN - Finish
Observe the following guidelines when using this criterion:
❑ The Protocol variable must be left blank or set to IP.
❑ The IP Protocol variable must be left blank or set to TCP.
❑ A classifier cannot contain both a TCP flag and a UDP source
and/or destination port.
Classifier
Guidelines
Here are the guidelines to follow when creating a classifier:
❑ Each classifier represents a separate traffic flow.
❑ The variables within a classifier are linked by AND. The more
variables specified within a classifier, the more specific it becomes
in terms of the defined flow. For instance, specifying both a source
IP address and a TCP destination port within the same classifier
defines a traffic flow that relates to IP packets containing both the
designated source IP address and TCP destination port. There are
restrictions on which variables can be used together in the same
classifier. For the restrictions, refer to Classifier Criteria on page
221.
❑ A classifier can be used for both an ACL and a QoS policy.
❑ You can apply the same classifier to more than one ACL or QoS
policy.
❑ A classifier without any defined variables applies to all packets.