Notes on debugging ssh connection problems

• Run the ssh client in verbose mode

  $ ssh -vvv user@host 
  

• On the server, check auth.log for errors

  $ sudo tail -f /var/log/auth.log 
  

  On Red Hat, it's /var/log/secure

• For more debugging info, (assuming you have control of the ssh server) run the sshd server in debug mode on another port

  $ sudo /usr/sbin/sshd -ddd -p 33333 
  

  Then specify the port, -p 33333 with the ssh client. e.g.

  $ ssh -vvv -p 33333 user@host 
  

Commands run on Ubuntu 10.04

sftp error: Received message too long 170160758¶

Problem was in the .bashrc. See http://www.snailbook.com/faq/sftp-corruption.auto.html