15-2
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 15 Configuring Access Control
Understanding How ACLs Work
Note
Except where specifically differentiated, the information and procedures in this chapter apply to
Supervisor Engine 32 with Policy Feature Card 3B/3BXL (PFC3B/PFC3BXL), Supervisor Engine 720
with PFC3A/PFC3B/PFC3BXL, Supervisor Engine 2 with PFC2, and Supervisor Engine 1 with PFC.
Understanding How ACLs Work
Traditionally, switches operated at Layer 2 only; switches switched traffic within a VLAN and routers
routed traffic between the VLANs. Catalyst 6500 series switches with the Multilayer Switch Feature
Card (MSFC) can accelerate packet routing between VLANs by using Layer 3 switching (Multilayer
Switching [MLS]). The switch first bridges the packet, the packet is then routed internally without going
to the router, and then the packet is bridged again to send it to its destination. During this process, the
switch can access control
all
packets that it switches
including
the packets that are bridged within a
VLAN.
Cisco IOS ACLs provide access control for the routed traffic between the VLANs, and the VLAN ACLs
(VACLs) provide access control for
all
packets.
The standard and extended Cisco IOS ACLs are used to classify the packets. The classified packets can
be subject to a number of features such as access control (security), encryption, policy-based routing,
and so on. The standard and extended Cisco IOS ACLs are configured only on the router interfaces and
applied on the routed packets.
The VACLs can provide access control that is based on the Layer 3 addresses for the IP and IPX
protocols. The unsupported protocols are access controlled through the MAC addresses. A VACL is
applied to all packets (bridged and routed) and can be configured on any VLAN interface. Once a VACL
is configured on a VLAN, all packets (routed or bridged) entering the VLAN are checked against the
VACL. The packets can either enter the VLAN through a switch port or through a router port after being
routed.
Note
With Supervisor Engine 720 (PFC3A/PFC3B/PFC3BXL) and Supervisor Engine 32
(PFC3B/PFC3BXL), the IPX routing is done through the software and the IPX Cisco IOS ACLs and IPX
VACLs are not supported. You can match the IPX packets using the MAC VACLs. You can enter the
ipx-arpa
keyword to match the IPX ARPA frames. Use 0xffff EtherType to match on IPX non-ARPA
frames and frames with an EtherType of 0xffff. For information on configuring the MAC VACLs, see
the
“Creating a Non-IP Version 4/Non-IPX VACL (MAC VACL) and Adding ACEs” section on
page 15-52
.
Hardware Requirements
The hardware that is required to configure the ACLs on Catalyst 6500 series switches is as follows:
•
Cisco IOS ACLs:
–
Supervisor Engine 1 and Policy Feature Card (PFC) and MSFC or MSFC2
–
Supervisor Engine 2 and PFC2 and MSFC2
–
Supervisor Engine 720 and PFC3A/PFC3B/PFC3BXL and MSFC3
–
Supervisor Engine 32 and PFC3B/PFC3BXL and MSFC2A