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Brian Thomas
Asked: 2018-08-23 11:47:31 +0800 CST

Why can't I have more than two SSH connections to a server?

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I am using Puppet PE 2017.3.5.0-1 on a CentOS7 AWS instance. When I SSH into this machine, to a default installation, I am getting limited to two connections only. When I try to connect again (from a 3rd terminal) the connection is closed automatically.

I'm not able to connect more than twice at the same time. I am using multiplexing.

I see a setting in /etc/ssh/sshd_config that says MaxSessions 2, which I highly suspect has something to do with it, but adjustments are not helping.

ssh

1 Answers

  1. The issue is in the /etc/ssh/sshd_config there is an entry in there MaxSessions. If this is set to a number 1, this means multiplexing is disabled. if it is set to 0, this means that login/shell/subsystem sessions are disallowed entirely. See here for a more descriptive answer on this here https://unix.stackexchange.com/questions/26170/sshd-config-maxsessions-parameter.

    Once you adjust this setting to 2 or more, (more than 2 in this case), or comment the line altogether, you have it correctly adjusted for more than 2 multiplexed connections now.

    The problem was for me, After these settings were adjusted, I still wasnt able to connect to more than 2, even if i disconnected entirely and tried again.

    I found the solution there was that you need to open the socket directory listed in .ssh/config, e.g. .ssh or .ssh/cm_socket, then remove the socket, because it retains this info. Once you delete the socket, ensuring you have restarted the sshd daemon, then your new settings will take effect.

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