SSH logins failing before success

1

I am running Ubuntu 12.04 Server, updated, to run a webserver on Tomcat 7.

I have about 1000 clients that are very very often using an RSYNC program to sync files with this server. Those RSyncs are using SSH with a certain user to open connections on the server.

The result is that my server is normally full of connections by the same user. About 5 connections per second at any given time.

Often, when I try to open a regular SSH connection with my Putty client, the connection fails before login with the error, "Server unexpectedly closed network connection". This happens about 6 times for 10 attempts, and for the other 4 attempts, it works normally and I am able to log in as any user.

Is there a overload of connections here?

The server statistics are very calm, saying less then 40% of network usage and less of 2% CPU.

How can I improve this?

--

I found the solution. There was a limit in terms of connections allowed.

To increase this limit, I simply activated the setting MaxStartups and set its value to 1000. Now there is no more problem.

I will however check the network and server usage to verify that the traffic is not too much.

Thank you anyway.

Vincent

Posted 2012-12-03T10:32:30.033

Reputation: 11

It's good to use something like fail2ban, if you are using that many connections, because it's rises number of possible attempts to break your password. – week – 2012-12-03T12:20:57.937

Well done for finding it! Could you please post your solution as an answer and accept it? It makes it easier to read for the next person with this problem. – terdon – 2012-12-03T12:23:38.837

No answers