Configuring Port-Based and User-Based Access Control (802.1X)

Terminology

Static VLAN: A VLAN that has been configured as “permanent” on the switch by using the CLI vlan < vid > command or the Menu interface.

Supplicant: The entity that must provide the proper credentials to the switch before receiving access to the network. This is usually an end-user work- station, but it can be a switch, router, or another device seeking network services.

Tagged Membership in a VLAN: This type of VLAN membership allows a port to be a member of multiple VLANs simultaneously. If a client connected to the port has an operating system that supports 802.1Q VLAN tagging, then the client can access VLANs for which the port is a tagged member. If the client does not support VLAN tagging, then it can access only a VLAN for which the port is an untagged member. (A port can be an untagged member of only one port-based VLAN at a time.) Where a port is a tagged member of a VLAN, 802.1X Open VLAN mode does not affect the port’s access to the VLAN unless the port is statically configured as a member of a VLAN that is also configured as the Unauthorized-Client or Authorized-Client VLAN. See also “Untagged Membership in a VLAN”.

Unauthorized-Client VLAN: A conventional, static VLAN statically configured on the switch. It is used to provide access to a client prior to authentication, and is sometimes termed a guest VLAN. It should be set up to allow an unauthenticated client to access only the initialization services necessary to establish an authenticated connection, plus any other desirable services whose use by an unauthenticated client poses no security threat to your network. (Note that an unauthenticated client has access to all network resources that have membership in the VLAN you designate as the Unauthorized-Client VLAN.) A port configured to use a given Unauthorized-Client VLAN does not have to be statically configured as a member of that VLAN as long as at least one other port on the switch is statically configured as a tagged or untagged member of the same Unauthorized-Client VLAN. An unauthorized-client VLAN is available on a port only if there is no authenticated client already using the port.

Untagged Membership in a VLAN: A port can be an untagged member of only one VLAN. (In the factory-default configuration, all ports on the switch are untagged members of the default VLAN.) An untagged VLAN membership is required for a client that does not support 802.1q VLAN tagging. A port can simultaneously have one untagged VLAN membership and multiple tagged VLAN memberships. Depending on how you configure 802.1X Open VLAN mode for a port, a statically configured, untagged VLAN membership may become unavailable while there is a client session on the port. See also “Tagged Membership in a VLAN”.

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