TACACS+ (Terminal Access Controller Access Control System) is an authentication protocol that allows a remote access server to forward a user's logon password to an authentication server to determine whether access can be allowed to a given system. TACACS+ and Remote Authentication
TACACS+ protocol is more reliable than RADIUS, as TACACS+ uses the Transmission Control Protocol (TCP) whereas RADIUS uses the User Datagram Protocol (UDP). Also, RADIUS combines authentication and authorization in a user profile, whereas TACACS+ separates the two operations.
TACACS+ offers the following advantages over RADIUS as the authentication device:
•TACACS+ is
•It supports
•It supports decoupled authentication, authorization, and accounting.
The following table describes the TACACS+ Server Configuration Menu options.
Table 82 TACACS+ Server Configuration Menu options
Command | Description |
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prisrv <IP address> | Defines the primary TACACS+ server address. |
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secsrv <IP address> | Defines the secondary TACACS+ server address. |
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secret | This is the shared secret between the switch and the TACACS+ server(s). |
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secret2 | This is the secondary shared secret between the switch and the TACACS+ |
| server(s). |
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port <TCP port number> | Enter the number of the TCP port to be configured, between 1 - 65000. The |
| default is 49. |
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retries | Sets the number of failed authentication requests before switching to a different |
| TACACS+ server. The range is |
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timeout | Sets the amount of time, in seconds, before a TACACS+ server authentication |
| attempt is considered to have failed. The range is |
| seconds. |
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telnet enabledisable | Enables or disables the TACACS+ back door for telnet. The telnet command |
| also applies to SSH/SCP connections and the |
| command does not apply when secure backdoor (secbd) is enabled. |
secbd enabledisable
Enables or disables the TACACS+ back door using secure password for telnet/SSH/ HTTP/HTTPS. This command does not apply when backdoor (telnet) is enabled.
cmap enabledisable
Enables or disables TACACS+
usermap | Maps a TACACS+ authorization level to a GbE2c user level. Enter a TACACS+ |
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useroperadminnone | authorization level |
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on | Enables the TACACS+ server. |
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off | Disables the TACACS+ server. |
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cur | Displays current TACACS+ configuration parameters. |
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IMPORTANT: If TACACS+ is enabled, you must login using TACACS+ authentication when connecting via the console or Telnet/SSH/HTTP/HTTPS. Backdoor for console is always enabled, so you can connect using notacacs and the administrator password even if the backdoor (telnet) or secure backdoor (secbd) are disabled.
If Telnet backdoor is enabled (telnet ena), type in notacacs as a backdoor to bypass TACACS+ checking, and use the administrator password to log into the switch. The switch allows this even if TACACS+ servers are available.
If secure backdoor is enabled (secbd ena), type in notacacs as a backdoor to bypass TACACS+ checking, and use the administrator password to log into the switch. The switch allows this only if TACACS+ servers are not available.
Configuration Menu 95