How to avoid two superusers are connected at the same time

[fernando_langreo]

Hi, all.

I need to configure a router with some users (local or RADIUS). Some of them will access with no superuser level and others will gain superuser (enable) access. The question or doubt I have is the next: I'd like that when a superuser connects by telnet or SSH (via vtty), another user with all privileges cannot connect or connect as no privieleges level. I'd like to config by this way in order to avoid that two administrator, at the same time, can configure the router. Is it possible?

Thanks in advance,

Fernando L.

[nspasov]

You can configure the router to only use one vty line at a time. For instance, you can run the following command:

line vty 0

This will only allow one vty connection (on line 0) at a time. Be careful though and make sure that you configure the proper session timeouts to ensure that a leftover session does not prevent anyone else from gaining access to the device. 

In addition, you can educate your admins to always run show users upon login to ensure that nobody else is logged in to the device and making changes. 

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