Disable multiple login[FC or *NIX]?

[Deepak Shrestha]

On 9/12/06, James Wilkinson <fedora at aprilcottage.co.uk> wrote:
> Deepak Shrestha wrote:
> > Is there a way to limit the particular user login only once in FC (or
> > *nix)??or disabling the double logins. Currently a user can log in
> > from different terminals using same account at same time and do
> > various things. I have tried also Putty and able to login using same
> > login name from windows machines. This is good for troubleshooting
> > purposes like when situation goes wrong, user can log in from
> > different terminal and fix it, but this also brings the anomali of two
> > persons being present at the different place at the same time.
> >
> > I guess this is not an concern for desktop users but exposing as
> > server might need considering this. At present my question is more on
> > a curiosity than of practical use.
>
> The short answer is that this is normal, expected, and only *very*
> rarely a problem. For almost all situations it's equivalent to having
> multiple terminal sessions open under the same username, which is
> something the vast majority of developers and a lot of power users do,
> so it gets tested a *lot*.
>
> And the reason it gets used a lot is quite simply that it's useful.
> People want to multitask, and having different terminals open means they
> can (for example) be composing an e-mail on one terminal while they
> refer to the output of a different program on another.
>
> As for the "anomaly" of one username being used from different places --
> it's not considered an anomaly. The computer *can't tell* which sessions
> are on screens that are physically close together (and GNU screen means
> that "physical location" can change).  And you might still want to use
> VNC (or equivalent) to sit at one desk, connect to another desktop, and
> start a connection there [1] -- which location is the user supposed to
> be at?
>
> I have once -- quite some time ago, on another list -- had it
> "explained" that it took too much computer power. Even then, the
> consensus of opinion was that computer power was cheap, and if you need
> to limit the number of users, there are better ways of doing it.
>
> James.
>
> [1] Remember that PuTTY and OpenSSH can be used for tunnelling
> connections, and you can send print jobs over PuTTY to a remote session.
>
> This is also useful to check that PuTTY / OpenSSH are actually working
> from the remote desktop.

Thanks for the info.