Dell POWEREDGE M1000E - Manual (Page 175)

Controlling Management Access 175
Figure 9-1. Basic TACACS+ Topology
You can configure the TACACS+ server list with one or more hosts defined
via their network IP address. You can also assign each a priority to determine
the order in which the TACACS+ client will contact them. TACACS+
contacts the server when a connection attempt fails or times out for a higher
priority server.
You can configure each server host with a specific connection type, port,
timeout, and shared key, or you can use global configuration for the key and
timeout.
The TACACS+ server can do the authentication itself, or redirect the request
to another back-end device. All sensitive information is encrypted and the
shared secret is never passed over the network; it is used only to encrypt the
data.
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Management Host
Primary TACACS+ Server
Backup TACACS+ Server
Management
Network
PowerConnect Switch