Failure to connect to the MX200 could be the result of the tunneling feature of SSH.
buffer_get_ret: trying to get more bytes 4 in buffer 0
buffer_get_int: buffer error
Try turning off tunneling in your ssh_config by commenting out the section responsible for tunneling.
Snippet of configuration.
EscapeChar ~
#Tunnel Yes
TunnelDevice any:any
Here are my troubleshooting steps to arrive at the solution. I tried removing all ssh preferences within my .ssh profile however that did not resolve the issue. So I finally compared the connections of a working an not working accounts and discovered that the standard user was unable to use ssh tunneling where as the root user could.
Working User Log
debug1: sys_tun_open: failed to upen tunnel control interface: Permission denied
Failed Root User Log
sys_tunopen:tunnel mode 1 fd7
I thought perhaps the ssh tunneling feature when enabled on the root user was causing the issue. Sure enough SSH Tunneling was causing the buffer_get_int and the buffer_get_ret errors.
