openssh unix dev - Apr 2020 - Is it possible to limit OpenSSH maximum number of clients?

C2 - PSA Sensitive

I am trying to limit the number of total OpenSSH connections to our Unix
systems.

At first, I have tried modifying OpenSSH configuration with `MaxSessions` and
`MaxStartups` options but with no success. They are ignored (maybe I don't
really understand what this options are intended to).

Using PAM limits in `/etc/security/limits.conf` I have succeed with
`maxsyslogins` directive:

```
# limit connections to the system to 10
*    -    maxsyslogins    10
```

It works, but we are limiting all kind of logins to the system, and using a
third party solution to apply limitations to OpenSSH. By example, we have
different kind of Unix (HP-UX, Solaris, Linux, AIX) and in not every server we
are using PAM for authentication.

I mean, does it exists a simpler and more direct way to do it? Something similar
to Apache `MaxClients` directive?

I don't find it and it's very strange for me that OpenSSH does not have
this possibility :-|.


---
Jos? Manuel Ciges Regueiro
Unix Systems Administrator & LAMP developer

Tel:?+34 608 57.05.06
Skype: ?jmciges
Email: ?jmanuel at ciges.net