Wireless/Redundant Edge Services xl Module Management and Configuration Guide WS.02.xx and greater

Table Of Contents
7-28
Access Control Lists (ACLs)
Configuring ACLs
3. From the Interface drop-down menu, select one of the following
interfaces:
uplink—the module’s internal uplink port
downlink—the module’s internal downlink port
an uplink VLAN configured on the module
4. Select the ACL to control incoming traffic on the selected interface. The
options available depend on the type of interface:
For VLAN interfaces, select an IP-type ACL from the IP ACL drop-down
menu.
For an uplink or downlink port, you can select ACLs from either the
IP ACL drop-down menu, the MAC ACL drop-down menu, or both.
When you apply both types of ACLs, the Wireless Edge Services xl
Module processes the MAC extended ACL first, so a rule in the MAC
ACL always takes precedence over a rule in the IP ACL. However, if
a frame is not selected by any of a MAC extended ACLs explicit rules,
the module sends the frame to be processed by the IP ACL.
5. Click the OK button to apply the ACL.
6. Click the Save link to preserve your configuration.
Using ACLs with DHCP Services
An ACL filters all traffic as soon as it arrives on the interface to which the ACL
is applied. Remember that most wireless stations have no IP address until they
receive one through DHCP. If you have applied an ACL to the VLAN (or tunnel)
associated with a WLAN, the module might drop stations’ DHCP requests
before they have the chance to receive a valid address.
To avoid problems, check all ACLs that filter traffic on a interface on which
DHCP requests might arrive: these ACLs must include a rule that permits those
requests. The best way to meet this requirement is to create an extended IP
ACL for the VLAN (or tunnel) in question and add a rule that permits any UDP
traffic destined to the DHCP server port (67).
Viewing ACL Statistics
You should check ACLs and verify that they are selecting traffic as they should.
To view statistics for your ACLs, select Security > ACLs and click the Statistics
tab. You can alternatively select Security > ACL Statistics.