Linux - Limite de sesiones en ssh

Hola a todos:

Necesito saber como se aumenta el limite de sesiones abiertas por ssh en Linux.
La distribución que utilizo es Ubuntu 12.04.

He estado leyendo por internet y comentan que hay que incluir/setear el parámetro MaxSessions XXXX en el fichero de configuración etc/ssh/sshd_config donde XXXX s el número máximo de sesiones que se quiere permitir, pero no me funciona.

Otra cosa, antes de tocar ninguna configuración, ¿Cómo se puede saber el número máximo de conexiones que soporta el sistema actualmente?

Gracias por todo

Un Saludo

Hola Jorge, hasta donde yo se, no hay limite de conexiones con diferentes usuarios... nosotros, hemos llegado a tener un sistema de acceso remoto con mas de 1000 conexiones simultaneas de ssh sin problema...

que error te da exactamente?

/etc/ssh/sshd_config

Yes it is possible to limit the number of concurrent login sessions, although most Linux distributions do not impose such limits in their default settings.

Linux is proper multi-user system by design and normally you shouldn't have any problems with having multiple concurrent SSH sessions for the same user.

The SSH server can impose such limits with the MaxSessions option in the configuration file. Through PAM you can impose such limits as well as others have already pointed out.

SSH Client

This is probably the easiest method as it doesn't require root or administrator access to the server and it could be applied to all SSH connections instead of just to a specific server.

What's going to happen is to basically keep the connection active even if the user is actually idle. This could be done by using the ServerAliveInterval option where the SSH client will send a null packet to the server over a set period of time just to keep the connection alive.

The following option will send the packet every 100 seconds;

ServerAliveInterval 100

- See more at: https://docs.oseems.com/general/application/ssh/disable-timeout#sthash.BOHdSzP5.dpuf