Security
Configuring RADIUS
Cisco 500 Series Stackable Managed Switch Administration Guide 440
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• Dead Time—Enter the number of minutes that elapse before a non-
responsive RADIUS server is bypassed for service requests. If the value is 0, 
the server is not bypassed. 
• Key String—Enter the default key string used for authenticating and 
encrypting between the device and the RADIUS server. This key must match 
the key configured on the RADIUS server. A key string is used to encrypt 
communications by using MD5. The key can be entered in Encrypted or 
Plaintext form. If you do not have an encrypted key string (from another 
device), enter the key string in plaintext mode and click Apply. The 
encrypted key string is generated and displayed.
This overrides the default key string if one has been defined.
• Source IPv4 Interface—Select the device IPv4 source interface to be used 
in messages for communication with the RADIUS server. 
• Source IPv6 Interface—Select the device IPv6 source interface to be 
used in messages for communication with the RADIUS server. 
NOTE If the Auto option is selected, the system takes the source IP address 
from the IP address defined on the outgoing interface.
STEP  4 Click Apply. The RADIUS default settings for the device are updated in the 
Running Configuration file.
To add a RADIUS server, click Add.
STEP  5 Enter the values in the fields for each RADIUS server. To use the default values 
entered in the RADIUS page, select Use Default. 
• Server Definition—Select whether to specify the RADIUS server by 
IP address or name.
• IP Version—Select the version of the IP address of the RADIUS server. 
• IPv6 Address Type—Select the IPv6 address type (if IPv6 is used). The 
options are:
- Link Local—The IPv6 address uniquely identifies hosts on a single 
network link. A link local address has a prefix of FE80, is not routable, and 
can be used for communication only on the local network. Only one link 
local address is supported. If a link local address exists on the interface, 
this entry replaces the address in the configuration.
- Global—The IPv6 address is a global Unicast IPV6 type that is visible and 
reachable from other networks.