ssh session hangs after authentication - SSH

This is a discussion on ssh session hangs after authentication - SSH ; I want to ssh to a RedHat server running OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003 The server hosts several websites. I have used three machines all from behind the same NAT 1) Debian unstable 4.6p1 OpenSSL 0.9.8e 2) Ubuntu 7.04: ...

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Thread: ssh session hangs after authentication

  1. ssh session hangs after authentication


    I want to ssh to a RedHat server running OpenSSH_3.9p1, OpenSSL 0.9.7a
    Feb 19 2003
    The server hosts several websites.

    I have used three machines all from behind the same NAT
    1) Debian unstable 4.6p1 OpenSSL 0.9.8e
    2) Ubuntu 7.04: ssh -v = OpenSSH_4.3p2 Debian-8ubuntu1, OpenSSL 0.9.8c
    05 Sep 2006
    3) Mac OS X

    The error log is below. The session hangs. Ctrl-C does not recover, I
    have to kill the terminal window.

    Note that a Windows machine running Putty succeeds, and on all three
    machines above, a Java ssh client succeeds.

    The problem exists on two accounts on the server.

    using env -i ssh ... makes no difference to the result.


    the connection hangs after authentication
    the ssh -v is attached

    The log file is very similar for all three configurations.
    I can't get any effective help from the Ubuntu or the Debian
    communities.


    im@antec1:/etc$ ssh -vvv timrich@tim-richardson.net
    OpenSSH_4.3p2 Debian-8ubuntu1, OpenSSL 0.9.8c 05 Sep 2006
    debug1: Reading configuration data /etc/ssh/ssh_config
    debug1: Applying options for *
    debug2: ssh_connect: needpriv 0
    debug1: Connecting to tim-richardson.net [72.34.40.85] port 22.
    debug1: Connection established.
    debug1: identity file /home/tim/.ssh/identity type -1
    debug1: identity file /home/tim/.ssh/id_rsa type -1
    debug1: identity file /home/tim/.ssh/id_dsa type -1
    debug1: Remote protocol version 2.0, remote software version
    OpenSSH_3.9p1
    debug1: match: OpenSSH_3.9p1 pat OpenSSH_3.*
    debug1: Enabling compatibility mode for protocol 2.0
    debug1: Local version string SSH-2.0-OpenSSH_4.3p2 Debian-8ubuntu1
    debug2: fd 3 setting O_NONBLOCK
    debug1: SSH2_MSG_KEXINIT sent
    debug1: SSH2_MSG_KEXINIT received
    debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-
    hellman-group14-sha1,diffie-hellman-group1-sha1
    debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
    debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
    cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-
    cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
    debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
    cbc,arcfour128,arcfour256,arcfour,aes192-cbc,aes256-cbc,rijndael-
    cbc@lysator.liu.se,aes128-ctr,aes192-ctr,aes256-ctr
    debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
    ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
    debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
    ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
    debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
    debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
    debug2: kex_parse_kexinit:
    debug2: kex_parse_kexinit:
    debug2: kex_parse_kexinit: first_kex_follows 0
    debug2: kex_parse_kexinit: reserved 0
    debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-
    hellman-group14-sha1,diffie-hellman-group1-sha1
    debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
    debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
    cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-
    ctr,aes192-ctr,aes256-ctr
    debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-
    cbc,arcfour,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se,aes128-
    ctr,aes192-ctr,aes256-ctr
    debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
    ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
    debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-
    ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
    debug2: kex_parse_kexinit: none,zlib
    debug2: kex_parse_kexinit: none,zlib
    debug2: kex_parse_kexinit:
    debug2: kex_parse_kexinit:
    debug2: kex_parse_kexinit: first_kex_follows 0
    debug2: kex_parse_kexinit: reserved 0
    debug2: mac_init: found hmac-md5
    debug1: kex: server->client aes128-cbc hmac-md5 none
    debug2: mac_init: found hmac-md5
    debug1: kex: client->server aes128-cbc hmac-md5 none
    debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
    debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
    debug2: dh_gen_key: priv key bits set: 109/256
    debug2: bits set: 532/1024
    debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
    debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
    debug3: check_host_in_hostfile: filename /home/tim/.ssh/known_hosts
    debug3: check_host_in_hostfile: match line 1
    debug3: check_host_in_hostfile: filename /home/tim/.ssh/known_hosts
    debug3: check_host_in_hostfile: match line 1
    debug1: Host 'tim-richardson.net' is known and matches the RSA host
    key.
    debug1: Found key in /home/tim/.ssh/known_hosts:1
    debug2: bits set: 506/1024
    debug1: ssh_rsa_verify: signature correct
    debug2: kex_derive_keys
    debug2: set_newkeys: mode 1
    debug1: SSH2_MSG_NEWKEYS sent
    debug1: expecting SSH2_MSG_NEWKEYS
    debug2: set_newkeys: mode 0
    debug1: SSH2_MSG_NEWKEYS received
    debug1: SSH2_MSG_SERVICE_REQUEST sent
    debug2: service_accept: ssh-userauth
    debug1: SSH2_MSG_SERVICE_ACCEPT received
    debug2: key: /home/tim/.ssh/identity ((nil))
    debug2: key: /home/tim/.ssh/id_rsa ((nil))
    debug2: key: /home/tim/.ssh/id_dsa ((nil))
    debug1: Authentications that can continue: publickey,password
    debug3: start over, passed a different list publickey,password
    debug3: preferred publickey,keyboard-interactive,password
    debug3: authmethod_lookup publickey
    debug3: remaining preferred: keyboard-interactive,password
    debug3: authmethod_is_enabled publickey
    debug1: Next authentication method: publickey
    debug1: Trying private key: /home/tim/.ssh/identity
    debug3: no such identity: /home/tim/.ssh/identity
    debug1: Trying private key: /home/tim/.ssh/id_rsa
    debug3: no such identity: /home/tim/.ssh/id_rsa
    debug1: Trying private key: /home/tim/.ssh/id_dsa
    debug3: no such identity: /home/tim/.ssh/id_dsa
    debug2: we did not send a packet, disable method
    debug3: authmethod_lookup password
    debug3: remaining preferred: ,password
    debug3: authmethod_is_enabled password
    debug1: Next authentication method: password
    timrich@tim-richardson.net's password:
    debug3: packet_send2: adding 48 (len 63 padlen 17 extra_pad 64)
    debug2: we sent a password packet, wait for reply
    debug1: Authentication succeeded (password).
    debug1: channel 0: new [client-session]
    debug3: ssh_session2_open: channel_new: 0
    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 0
    debug3: tty_make_modes: ospeed 38400
    debug3: tty_make_modes: ispeed 38400
    debug3: tty_make_modes: 1 3
    debug3: tty_make_modes: 2 28
    debug3: tty_make_modes: 3 127
    debug3: tty_make_modes: 4 21
    debug3: tty_make_modes: 5 4
    debug3: tty_make_modes: 6 255
    debug3: tty_make_modes: 7 255
    debug3: tty_make_modes: 8 17
    debug3: tty_make_modes: 9 19
    debug3: tty_make_modes: 10 26
    debug3: tty_make_modes: 12 18
    debug3: tty_make_modes: 13 23
    debug3: tty_make_modes: 14 22
    debug3: tty_make_modes: 18 15
    debug3: tty_make_modes: 30 0
    debug3: tty_make_modes: 31 0
    debug3: tty_make_modes: 32 0
    debug3: tty_make_modes: 33 0
    debug3: tty_make_modes: 34 0
    debug3: tty_make_modes: 35 0
    debug3: tty_make_modes: 36 1
    debug3: tty_make_modes: 37 0
    debug3: tty_make_modes: 38 1
    debug3: tty_make_modes: 39 1
    debug3: tty_make_modes: 40 0
    debug3: tty_make_modes: 41 1
    debug3: tty_make_modes: 50 1
    debug3: tty_make_modes: 51 1
    debug3: tty_make_modes: 52 0
    debug3: tty_make_modes: 53 1
    debug3: tty_make_modes: 54 1
    debug3: tty_make_modes: 55 1
    debug3: tty_make_modes: 56 0
    debug3: tty_make_modes: 57 0
    debug3: tty_make_modes: 58 0
    debug3: tty_make_modes: 59 1
    debug3: tty_make_modes: 60 1
    debug3: tty_make_modes: 61 1
    debug3: tty_make_modes: 62 0
    debug3: tty_make_modes: 70 1
    debug3: tty_make_modes: 71 0
    debug3: tty_make_modes: 72 1
    debug3: tty_make_modes: 73 0
    debug3: tty_make_modes: 74 0
    debug3: tty_make_modes: 75 0
    debug3: tty_make_modes: 90 1
    debug3: tty_make_modes: 91 1
    debug3: tty_make_modes: 92 0
    debug3: tty_make_modes: 93 0
    debug1: Sending environment.
    debug3: Ignored env SSH_AGENT_PID
    debug3: Ignored env SHELL
    debug3: Ignored env DESKTOP_STARTUP_ID
    debug3: Ignored env TERM
    debug3: Ignored env GTK_RC_FILES
    debug3: Ignored env WINDOWID
    debug3: Ignored env USER
    debug3: Ignored env LS_COLORS
    debug3: Ignored env SSH_AUTH_SOCK
    debug3: Ignored env GNOME_KEYRING_SOCKET
    debug3: Ignored env SESSION_MANAGER
    debug3: Ignored env USERNAME
    debug3: Ignored env PATH
    debug3: Ignored env DESKTOP_SESSION
    debug3: Ignored env GDM_XSERVER_LOCATION
    debug3: Ignored env PWD
    debug1: Sending env LANG = en_AU.UTF-8
    debug2: channel 0: request env confirm 0
    debug3: Ignored env GDM_LANG
    debug3: Ignored env GDMSESSION
    debug3: Ignored env HISTCONTROL
    debug3: Ignored env SHLVL
    debug3: Ignored env HOME
    debug3: Ignored env LANGUAGE
    debug3: Ignored env GNOME_DESKTOP_SESSION_ID
    debug3: Ignored env LOGNAME
    debug3: Ignored env DBUS_SESSION_BUS_ADDRESS
    debug3: Ignored env LESSOPEN
    debug3: Ignored env DISPLAY
    debug3: Ignored env LESSCLOSE
    debug3: Ignored env COLORTERM
    debug3: Ignored env XAUTHORITY
    debug3: Ignored env _
    debug3: Ignored env OLDPWD
    debug2: channel 0: request shell confirm 0
    debug2: fd 3 setting TCP_NODELAY
    debug2: callback done
    debug2: channel 0: open confirm rwindow 0 rmax 32768

    that is the last message. The terminal hangs. ctrl-c can not interrupt.


  2. Re: ssh session hangs after authentication

    > the connection hangs after authentication
    > the ssh -v is attached


    I've been getting that same hang after "debug2: channel 0: open confirm
    rwindow 0 rmax 32768" for a few weeks now. (I rarely ssh out from this
    particular machine, so it's hard to tell exactly when it stopped
    working. For completeness, I'll mention that process occasionally hangs
    right after "debug1: identity file /root/.ssh/id_dsa type -1". Not sure
    why, but let's consider that secondary.)

    I'm using OpenSSH on a 2.6.7 kernel:

    OpenSSH_3.8.1p1 Debian-8.sarge.2, OpenSSL 0.9.7d 17 Mar 2004.

    This machine used to work just fine, and I'm not aware of having changed
    anything with it. In a lab with a *bunch* of machines, I haven't yet
    found one that I am able to ssh into, so the problem seems to be pervasive.

    I saw a post where somebody was speculating that there might be a DNS
    resolution problem right after authentication, but the issue persists
    even when I specify the target machine by IP address.

    > The terminal hangs. ctrl-c can not interrupt.


    Same thing here. I have to kill the process.

  3. Re: ssh session hangs after authentication

    On Jul 18, 7:17 pm, Neil Steiner wrote:
    > > the connection hangs after authentication
    > > the ssh -v is attached

    >
    > I've been getting that same hang after "debug2: channel 0: open confirm
    > rwindow 0 rmax 32768" for a few weeks now. (I rarely ssh out from this
    > particular machine, so it's hard to tell exactly when it stopped
    > working. For completeness, I'll mention that process occasionally hangs
    > right after "debug1: identity file /root/.ssh/id_dsa type -1". Not sure
    > why, but let's consider that secondary.)
    >
    > I'm using OpenSSH on a 2.6.7 kernel:
    >
    > OpenSSH_3.8.1p1 Debian-8.sarge.2, OpenSSL 0.9.7d 17 Mar 2004.
    >
    > This machine used to work just fine, and I'm not aware of having changed
    > anything with it. In a lab with a *bunch* of machines, I haven't yet
    > found one that I am able to ssh into, so the problem seems to be pervasive.
    >
    > I saw a post where somebody was speculating that there might be a DNS
    > resolution problem right after authentication, but the issue persists
    > even when I specify the target machine by IP address.
    >
    > > The terminal hangs. ctrl-c can not interrupt.

    >
    > Same thing here. I have to kill the process.


    For me, I can also reproduce the problem in reverse. I set up sshd on
    a debian box at home and set up the firewall.
    >From the same Debian box, I used the Java ssh client to log on to my

    webhoste (Redhat). I tried ssh -vvv back to my home computer. The log
    file showed exactly the same problem. My password was accepted, and
    then the session hangs, with exactly the same final message from the
    log file.

    Since the problem affects three home machines all running different
    versions of openssh, it is not machine specific.
    I wonder now about my router, a D-LINK. But since ssh works when using
    non openssh clients, I still think this can be called a bug in openssh.


  4. Re: ssh session hangs after authentication

    > For me, I can also reproduce the problem in reverse. I set up sshd on
    > a debian box at home and set up the firewall.
    >>From the same Debian box, I used the Java ssh client to log on to my

    > webhoste (Redhat). I tried ssh -vvv back to my home computer. The log
    > file showed exactly the same problem. My password was accepted, and
    > then the session hangs, with exactly the same final message from the
    > log file.
    >
    > Since the problem affects three home machines all running different
    > versions of openssh, it is not machine specific.
    > I wonder now about my router, a D-LINK. But since ssh works when using
    > non openssh clients, I still think this can be called a bug in openssh.


    I'm getting this problem with two machines that are plugged into the
    same hub, and no firewalling as far as I know. There's certainly no
    router involved.

  5. Re: ssh session hangs after authentication

    On Jul 19, 7:28 pm, Neil Steiner wrote:
    > > For me, I can also reproduce the problem in reverse. I set up sshd on
    > > a debian box at home and set up the firewall.
    > >>From the same Debian box, I used the Java ssh client to log on to my

    > > webhoste (Redhat). I tried ssh -vvv back to my home computer. The log
    > > file showed exactly the same problem. My password was accepted, and
    > > then the session hangs, with exactly the same final message from the
    > > log file.

    >
    > > Since the problem affects three home machines all running different
    > > versions of openssh, it is not machine specific.
    > > I wonder now about my router, a D-LINK. But since ssh works when using
    > > non openssh clients, I still think this can be called a bug in openssh.

    >
    > I'm getting this problem with two machines that are plugged into the
    > same hub, and no firewalling as far as I know. There's certainly no
    > router involved.


    I found an update to my router firmware on the German site of D-Link.
    It was a major update; with much new functionality and a complete
    upgrade of the user-interface. The openssh problem has gone. I also
    had problems with IPv6 when the router was acting as the DNS server
    passed to DHCP clients, and I would not be surprised to find they have
    gone as well.
    To help others, my router is a DSL-564T and the new firmware is dated
    20060831



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