Cisco Catalyst 4500 Series, Software Configuration Manual

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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 49 Configuring 802.1X Port-Based Authentication
About 802.1X Port-Based Authentication
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We do not recommend per-user ACLs with an MDA-enabled port. An authorized device with a per-user ACL policy might
impact traffic on both the voice and data VLANs of the port. If used, only one device on the port should enforce per-user
ACLs.
Multi-Authentication Per User VLAN Authentication
The Multi-auth Per User VLAN assignment feature allows you to create multiple operational access VLANs based on VLANs
assigned to the clients on the port that has a single configured access VLAN. The port configured as an access port where the
traffic for all the VLANs associated with data domain is not dot1q tagged, and these VLANs are treated as native VLANs.
The number of hosts per multi-auth port is 8, however there can be more hosts.
Note
The Multi-auth Per User VLAN assignment feature is not supported for Voice domain. All clients in
Voice domain on a port must use the same VLAN.
The following scenarios are associated with the multi-auth Per User VLAN assignments:
Scenario One
When a hub is connected to an access port, and the port is configured with an access VLAN (V0).
The host (H1) is assigned to VLAN (V1) through the hub. The operational VLAN of the port is changed to V1. This behavior
is similar on a single-host or multi-domain-auth port.
When a second host (H2) is connected and gets assigned to VLAN ( V2), the port will have two operational VLANs (V1 and
V2). If H1 and H2 sends untagged ingress traffic, H1 traffic is mapped to VLAN (V1) and H2 traffic to VLAN (V2), all egress
traffic going out of the port on VLAN (V1) and VLAN (V2) are untagged.
If both the hosts, H1 and H2 are logged out or the sessions are removed due to some reason then VLAN (V1) and VLAN (V2)
are removed from the port, and the configured VLAN (V0) is restored on the port.
Scenario Two
When a hub is connected to an access port, and the port is configured with an access VLAN (V0). The host (H1) is assigned to
VLAN (V1) through the hub. The operational VLAN of the port is changed to V1.
When a second host (H2) is connected and gets authorized without explicit vlan policy, H2 is expected to use the configured
VLAN (V0) that is restored on the port. All egress traffic going out of two operational VLANs, VLAN (V0) and VLAN (V1)
are untagged.
If host (H2) is logged out or the session is removed due to some reason then the configured VLAN (V0) is removed from the
port, and VLAN (V1) becomes the only operational VLAN on the port.
Scenario Three
When a hub is connected to an access port in open mode, and the port is configured with an access VLAN (V0).
The host (H1) is assigned to VLAN (V1) through the hub. The operational VLAN of the port is changed to V1. When a second
host (H2) is connected and remains unauthorized, it still has access to operational VLAN (V1) due to open mode.
If host H1 is logged out or the session is removed due to some reason, VLAN (V1) is removed from the port and host (H2) gets
assigned to VLAN (V0).
Note
The combination of Open mode and VLAN assignment has an adverse affect on host (H2) because it has
an IP address in the subnet that corresponds to VLAN (V1).