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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 8 Configuri ng 802.1X Port-Bas ed Authenticat ion Configuring 802.1X Authentication
This example shows how to enable AAA and 802.1X on Fast Ethernet port 0/1:
Switch# configure terminal
Switch(config)# aaa new-model
Switch(config)# aaa authentication dot1x default group radius
Switch(config)# interface fastethernet0/1
Switch(config-if)# dot1x port-control auto
Switch(config-if)# end

Configuring the Switch-to-RADIUS-Server Communication

RADIUS security servers are identified by their host name or IP address, host name and specific UDP
port num bers, or IP addr ess and spec ific UDP port n umbers. The co mbination of t he IP address an d UDP
port number creates a unique identifier, which enables RADIUS requests to be sent to multiple UDP
ports on a server at the same IP address. If two diff erent host entries on the same RADIUS server are
configured for the same service—for example, auth enticatio n—the second host entry configured acts as
the fail-over backup to the first one. The RADIUS host entries are tried in the order that they were
configured.
Beginning in privileged EXEC mode, follow these steps to configure the RADIUS server parameters on
the switch . This procedure is requir ed.
To delete the specified RADIUS server, use the no ra dius -server hos t {hostname | ip-address} global
configurati on comm a nd.
Command Purpose
Step 1 configure terminal Enter glob al co nfiguration mo de.
Step 2 radius-server host {hostname |
ip-address} auth-port port-number key
string
Configure the RADIUS server parameter s on the switch.
For hostname | ip-address, specify th e host name o r I P add re ss o f th e
remote RA DIU S server.
For auth-port port-number, specify the UDP destination port for
authen ticat ion reque sts. The de fault is 1812.
For key string, specify the authentication and encryption key us ed
betwee n the switc h and the RA DIUS dae mon runn ing on the RADIU S
server . The key is a text string that must match the encryption key used on
the RADIUS server.
Note Always c onfigure the key as th e la st i te m in the r adi us - server
host comma nd syntax beca use lead ing space s are igno red, but
spac es wit hin a nd at the en d of the ke y are u sed . If you u se sp aces
in the key, do not enclose th e key in quotation m arks unless the
quotation ma rk s are par t of the key. Thi s key must m atch the
encr yptio n used on t he R AD I US daem on .
If you want to use multiple RADIUS servers, re-enter this command.
Step 3 end Return to privileged EXEC mode.
Step 4 show running-config Verify your entries.
Step 5 copy running-config startup-config (Optional) Save your entries in the configuration file.