Router Acls - Cisco Catalyst 4500 series Administration Manual

About ACLs
ACLs permit or deny packet forwarding based on how the packet matches the entries in the ACL. For
example, you can use access lists to allow one host to access a part of a network, but prevent another
host from accessing the same part. In
access the Human Resources network, but prevent Host B from accessing the same network.
Figure 54-1
Port ACLs
You can also apply ACLs to Layer 2 interfaces on a switch. Port ACLs are supported on physical
interfaces and EtherChannel interfaces.
The following access lists are supported on Layer 2 interfaces:
•
•
•
•
As with router ACLs, the switch examines ACLs associated with features configured on a given interface
and permits or denies packet forwarding based on how the packet matches the entries in the ACL. In the
example in
would allow Host A to access the Human Resources network, but prevent Host B from accessing the
same network.
When you apply a port ACL to a trunk port, the ACL filters traffic on all VLANs present on the trunk
port. When you apply a port ACL to a port with voice VLAN, the ACL filters traffic on both data and
voice VLANs.
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
54-4
Using ACLs to Control Traffic to a Network
Catalyst 4500 series switch
Si
Human
Resources
network
= ACL denying traffic from Host B
and permitting traffic from Host A
= Packet
Standard IP access lists using source addresses
Extended IP access lists using source and destination addresses and optional protocol type
information
IPv6 access lists using source and destination addresses and optional protocol type information
MAC extended access lists using source and destination MAC addresses and optional protocol type
information
Figure 54-1, if all workstations were in the same VLAN, ACLs applied at the Layer 2 input
Chapter 54
Figure 54-1, ACLs applied at the router input allow Host A to
Host A
Host B
Research &
Development
network
Configuring Network Security with ACLs
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