Limit concurrent SSH sessions

[Amit Prajapati]

Hi Jakub

Thanks for your reply!!

I tried following steps:
1. "UsePAM yes" is set in /etc/ssh/sshd_config file.
2. Added "session required pam_limits.so" in /etc/pam.d/sshd file.
3. Added " *     hard      maxlogins      5 " in /etc/security/limits.conf
 file.

Still, I am not able to restrict the max session to 5. Am I missing
something?
Also I don't want to put this limit per user, I want to put the limit for
max sessions from any user to 5.

Thanks & Regards,
Amit

On Tue, Aug 20, 2019 at 3:05 PM Jakub Jelen <jjelen at redhat.com> wrote:

> On Tue, 2019-08-20 at 14:05 +0530, Amit Prajapati wrote:
> > Hi,
> >
> > For one of my application, for accepting the ssh connection on
> > different
> > namespaces, I am instantiating "sshd service" on different
> > namespaces. I am
> > able to  create ssh connection on each namespcae but I want to put a
> > limitation on max concurrent ssh connection to 5 for each namespace.
> > Is
> > there a way to achieve it using openssh.
>
> I don't think there is a way to do that in the OpenSSH itself, since
> each of the ssh sessions on the server is separate process without any
> information about the others.
>
> But you can simply do that using pam, for example using pam_limits
> module, and maxlogins option in limits.conf.
>
> Regards,
> --
> Jakub Jelen
> Senior Software Engineer
> Security Technologies
> Red Hat, Inc.
>
>