Motorola WS5100 Series Reference Manual page 288

6-18 WS5100 Series Switch System Reference Guide
• Wireless LAN ACLs - A Wireless LAN ACL is designed to filter/mark packets based on the wireless LAN
from which they arrived rather than filtering the packets arrived on L2 ports.
For more information, see
• Router ACLs
• Port ACLs
• Wireless LAN ACLs
• ACL Actions
• Precedence Order
6.5.1.1 Router ACLs
Router ACLs are applied to Layer 3 or VLAN interfaces. If an ACL is already applied in a particular direction
on an interface, applying a new one will replace the existing ACL. Router ACLs are applicable only if the
switch acts as a gateway, and traffic is inbound only.
The switch supports two types of Router ACLs:
• Standard IP ACL—Uses the source IP address as matching criteria.
• Extended IP ACL—Uses the source IP address, destination IP address and IP protocol type as basic
matching criteria. It can also include other parameters specific to a protocol type (like source and
destination port for TCP/UDP protocols).
Router ACLs are stateful and are not applied on every packet routed through the switch. Whenever a packet
is received from a Layer 3 interface, it is examined against existing sessions to determine if it belongs to an
established session. ACLs are applied on the packet in the following manner.
1. If the packet matches an existing session, it is not matched against ACL rules and the session decides
where to send the packet.
2. If no existing sessions match the packet, it is matched against ACL rules to determine whether to accept
or reject it. If ACL rules accept the packet, a new session is created and all further packets belonging to
that session are allowed. If ACL rules reject the packet, no session is established.
A session is computed based on:
• Source IP address
• Destination IP address
• Source Port
• Destination Port
• ICMP identifier
• Incoming interface index
• IP Protocol
NOTE: Port and router ACLs can be applied only in an inbound direction. WLAN ACLs
support applying ACLs in the inbound and outbound direction.
Each session has a default idle time-out interval. If no packets are received within this interval, the session
is terminated and a new session must be initiated. These intervals are fixed and cannot be configured by the
user.