Limits of SSH Connections and Sessions

Maximum number of sessions per connection

MaxSessions Specifies the maximum number of open sessions permitted per network connection. The default is 10.

MaxSessions=10

Added a MaxSessions option to sshd_config(5) to allow control of the number of multiplexed sessions supported over a single TCP connection. This allows increasing the number of allowed sessions above the previous default of 10, disabling connection multiplexing (MaxSessions=1) or disallowing login/shell/subsystem sessions entirely (MaxSessions=0).

Maximum number of connections per user

You can limit the number of concurrent logins a user can have over SSH by modifying /etc/security/limits.conf

user-name           -       maxlogins       1

See also

• sshd_config MaxSessions parameter
• Limit The Number Of SSH Logins Per User/Group/System