Re: Why does my ssh session terminate immediately?
Hi Jean-Marc,
thanks for your suggestions. See the results inline.
Jean-Marc <jean-marc@6jf.be> writes:
> On Wed, 24 Apr 2013 05:03:53 +0200, Andreas Leha
> <andreas.leha@med.uni-goettingen.de> wrote:
> Hi Andreas,
>
> Did you check your sshd config' ?
> You can do it running:
> sshd -t
I get nothing -- which I think is good in this case.
>
> You can also make tests by running you sshd in debug mode.
> Just start it on another port to not disturb the main one:
> sshd -de -p 8022
>
> and try a connection on this SSH from your client:
> ssh -p 8022 yourhost
>
> and check what happens on your server.
>
I did that, here is the result:
,----[ on the server -- before a connection attempt ]
| > /usr/sbin/sshd -de -p 8022
| debug1: sshd version OpenSSH_5.5p1 Debian-6+squeeze3
| debug1: read PEM private key done: type RSA
| debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
| debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
| debug1: private host key: #0 type 1 RSA
| debug1: read PEM private key done: type DSA
| debug1: Checking blacklist file /usr/share/ssh/blacklist.DSA-1024
| debug1: Checking blacklist file /etc/ssh/blacklist.DSA-1024
| debug1: private host key: #1 type 2 DSA
| debug1: rexec_argv[0]='/usr/sbin/sshd'
| debug1: rexec_argv[1]='-de'
| debug1: rexec_argv[2]='-p'
| debug1: rexec_argv[3]='8022'
| Set /proc/self/oom_adj from 0 to -17
| debug1: Bind to port 8022 on 0.0.0.0.
| Server listening on 0.0.0.0 port 8022.
| debug1: Bind to port 8022 on ::.
| Server listening on :: port 8022.
`----
,----[ on the server -- during a connection attempt ]
| debug1: Server will not fork when running in debugging mode.
| debug1: rexec start in 5 out 5 newsock 5 pipe -1 sock 8
| debug1: sshd version OpenSSH_5.5p1 Debian-6+squeeze3
| debug1: read PEM private key done: type RSA
| debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
| debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
| debug1: private host key: #0 type 1 RSA
| debug1: read PEM private key done: type DSA
| debug1: Checking blacklist file /usr/share/ssh/blacklist.DSA-1024
| debug1: Checking blacklist file /etc/ssh/blacklist.DSA-1024
| debug1: private host key: #1 type 2 DSA
| debug1: inetd sockets after dupping: 3, 3
| Connection from 192.168.2.101 port 55650
| debug1: Client protocol version 2.0; client software version OpenSSH_6.0p1 Debian-4
| debug1: match: OpenSSH_6.0p1 Debian-4 pat OpenSSH*
| debug1: Enabling compatibility mode for protocol 2.0
| debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-6+squeeze3
| debug1: permanently_set_uid: 101/65534
| debug1: list_hostkey_types: ssh-rsa,ssh-dss
| debug1: SSH2_MSG_KEXINIT sent
| debug1: SSH2_MSG_KEXINIT received
| debug1: kex: client->server aes128-ctr hmac-md5 none
| debug1: kex: server->client aes128-ctr hmac-md5 none
| debug1: SSH2_MSG_KEX_DH_GEX_REQUEST received
| debug1: SSH2_MSG_KEX_DH_GEX_GROUP sent
| debug1: expecting SSH2_MSG_KEX_DH_GEX_INIT
| debug1: SSH2_MSG_KEX_DH_GEX_REPLY sent
| debug1: SSH2_MSG_NEWKEYS sent
| debug1: expecting SSH2_MSG_NEWKEYS
| debug1: SSH2_MSG_NEWKEYS received
| debug1: KEX done
| debug1: userauth-request for user root service ssh-connection method none
| debug1: attempt 0 failures 0
| debug1: PAM: initializing for "root"
| debug1: PAM: setting PAM_RHOST to "192.168.2.101"
| debug1: PAM: setting PAM_TTY to "ssh"
| Failed none for root from 192.168.2.101 port 55650 ssh2
| debug1: userauth-request for user root service ssh-connection method publickey
| debug1: attempt 1 failures 0
| debug1: test whether pkalg/pkblob are acceptable
| debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
| debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
| debug1: temporarily_use_uid: 0/0 (e=0/0)
| debug1: trying public key file /root/.ssh/authorized_keys
| debug1: fd 4 clearing O_NONBLOCK
| debug1: matching key found: file /root/.ssh/authorized_keys, line 1
| Found matching RSA key: 47:7c:14:dd:25:54:14:0d:d8:cf:c5:24:44:d4:7b:c2
| debug1: restore_uid: 0/0
| Postponed publickey for root from 192.168.2.101 port 55650 ssh2
| debug1: userauth-request for user root service ssh-connection method publickey
| debug1: attempt 2 failures 0
| debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
| debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
| debug1: temporarily_use_uid: 0/0 (e=0/0)
| debug1: trying public key file /root/.ssh/authorized_keys
| debug1: fd 4 clearing O_NONBLOCK
| debug1: matching key found: file /root/.ssh/authorized_keys, line 1
| Found matching RSA key: 47:7c:14:dd:25:54:14:0d:d8:cf:c5:24:44:d4:7b:c2
| debug1: restore_uid: 0/0
| debug1: ssh_rsa_verify: signature correct
| debug1: do_pam_account: called
| Accepted publickey for root from 192.168.2.101 port 55650 ssh2
| debug1: monitor_child_preauth: root has been authenticated by privileged process
| debug1: PAM: establishing credentials
| debug1: Entering interactive session for SSH2.
| debug1: server_init_dispatch_20
| debug1: server_input_channel_open: ctype session rchan 0 win 1048576 max 16384
| debug1: input_session_request
| debug1: channel 0: new [server-session]
| debug1: session_new: session 0
| debug1: session_open: channel 0
| debug1: session_open: session 0: link with channel 0
| debug1: server_input_channel_open: confirm session
| debug1: server_input_global_request: rtype no-more-sessions@openssh.com want_reply 0
| debug1: server_input_channel_req: channel 0 request pty-req reply 1
| debug1: session_by_channel: session 0 channel 0
| debug1: session_input_channel_req: session 0 req pty-req
| debug1: Allocating pty.
| debug1: session_pty_req: session 0 alloc /dev/pts/0
| debug1: SELinux support disabled
| debug1: server_input_channel_req: channel 0 request env reply 0
| debug1: session_by_channel: session 0 channel 0
| debug1: session_input_channel_req: session 0 req env
| debug1: server_input_channel_req: channel 0 request shell reply 1
| debug1: session_by_channel: session 0 channel 0
| debug1: session_input_channel_req: session 0 req shell
| debug1: Setting controlling tty using TIOCSCTTY.
| debug1: Received SIGCHLD.
| debug1: session_by_pid: pid 895
| debug1: session_exit_message: session 0 channel 0 pid 895
| debug1: session_exit_message: release channel 0
| debug1: session_pty_cleanup: session 0 release /dev/pts/0
| debug1: session_by_channel: session 0 channel 0
| debug1: session_close_by_channel: channel 0 child 0
| debug1: session_close: session 0 pid 0
| debug1: channel 0: free: server-session, nchannels 1
| Received disconnect from 192.168.2.101: 11: disconnected by user
| debug1: do_cleanup
| debug1: PAM: cleanup
| debug1: PAM: closing session
| debug1: PAM: deleting credentials
`----
,----[ on the client side ]
| > ssh -p 8022 root@192.168.2.109
| Linux debian 2.6.32-5-kirkwood #1 Sun May 6 16:57:51 UTC 2012 armv5tel
|
| The programs included with the Debian GNU/Linux system are free software;
| the exact distribution terms for each program are described in the
| individual files in /usr/share/doc/*/copyright.
|
| Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
| permitted by applicable law.
| Last login: Wed Apr 24 02:54:10 2013 from 192.168.2.101
| debug1: PAM: reinitializing credentials
| debug1: permanently_set_uid: 0/0
| Environment:
| LANG=C
| USER=root
| LOGNAME=root
| HOME=/root
| PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/bin/X11
| MAIL=/var/mail/root
| SHELL=/bin/bash
| SSH_CLIENT=192.168.2.101 55650 8022
| SSH_CONNECTION=192.168.2.101 55650 192.168.2.109 8022
| SSH_TTY=/dev/pts/0
| TERM=screen
| Connection to 192.168.2.109 closed
`----
So it says 'disconnected by user'? I might mention, that can login to
(all) other machines with that client without problems.
Regards,
Andreas
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