I am connecting from Linux via SSH to a Windows machine running SSH in Cygwin. I authenticate with a certificate. The session opens but closes immediately thereafter. With password authentication it works well - the session remains active until I log out.
I have neither knowledge nor control over the server setup but their admin is unable to troubleshoot it as he has limited knowledge of both Linux and SSH himself.
So I am trying to determine what may be the causes of this behavior so that I can pass this information to the admin who can then fix their setup.
When I run ssh with the verbose output turned on, I get this:
debug1: Trying private key: /home/user/.ssh/identity debug1: Offering public key: /home/user/.ssh/id_rsa debug2: we sent a publickey packet, wait for reply debug1: Server accepts key: pkalg ssh-rsa blen 277 debug2: input_userauth_pk_ok: fp [some MAC-like sequence] debug1: PEM_read_PrivateKey failed debug1: read PEM private key done: type <unknown> Enter passphrase for key '/home/user/.ssh/id_rsa': debug1: read PEM private key done: type RSA debug1: Authentication succeeded (publickey). debug1: channel 0: new [client-session] debug2: channel 0: send open debug1: Entering interactive session. debug2: callback start debug2: client_session2_setup: id 0 debug2: channel 0: request pty-req confirm 1 debug1: Sending environment. debug1: Sending env LANG = en_US.UTF-8 debug2: channel 0: request env confirm 0 debug2: channel 0: request shell confirm 1 debug2: fd 3 setting TCP_NODELAY debug2: callback done debug2: channel 0: open confirm rwindow 0 rmax 32768 debug2: channel_input_status_confirm: type 99 id 0 debug2: PTY allocation request accepted on channel 0 debug2: channel 0: rcvd adjust 131072 debug2: channel_input_status_confirm: type 99 id 0 debug2: shell request accepted on channel 0 Last login: Mon Oct 18 20:19:58 2010 from ip-xyz debug2: channel 0: rcvd eof debug2: channel 0: output open -> drain debug2: channel 0: obuf empty debug2: channel 0: close_write debug2: channel 0: output drain -> closed debug1: client_input_channel_req: channel 0 rtype exit-status reply 0 debug2: channel 0: rcvd close debug2: channel 0: close_read debug2: channel 0: input open -> closed debug2: channel 0: almost dead debug2: channel 0: gc: notify user debug2: channel 0: gc: user detached debug2: channel 0: send close debug2: channel 0: is dead debug2: channel 0: garbage collecting debug1: channel 0: free: client-session, nchannels 1 Connection to example.com closed. Transferred: sent 2544, received 3160 bytes, in 0.2 seconds Bytes per second: sent 10327.0, received 12827.5 debug1: Exit status 255
(I edited some identifying but probably meaningless bits)
So it seems that right after logging in the client receives some bits it does not like and closes the connection.
(this is a cross-post from SU http://superuser.com/questions/200756/, where it arguably does not belong)