ssh connection closes after successful login
Solution 1
Because you get the same problem when connecting from localhost, it's probably a fault at the servers-side.
With the information given currently, it is quite hard to figure out what went wrong.
Take a look at the server-side logs : grep 'sshd' /var/log/auth.log
You could try using ssh -v
or ssh -vv
to get a more detailed output on the client side, but I suppose the auth.log is more promising.
Once that information is gathered, you could edit your question to describe the problem more properly!
Edit:
Another option might be setting "LogLevel INFO" to "LogLevel DEBUG" in /etc/sshd_config
and gathering more output from the server.
Please go through your logs before posting them, the man page warns that a high LogLevel might impair privacy.
Solution 2
Here's another possiblity, in case anyone finds this while searching like I did: same symptoms, SSH session closes after entering password. My variation was that SSH from the server to itself worked, but would fail after authentication from any external source.
I'd looked at most of the above suggestions already. When I finally ran sshd with DEBUG3 I noticed it was doing a reverse DNS look up on the source IP.
What I finally found was that the DNS resolvers had been set up originally while we were in the middle of upgrading the DNS servers, so the first resolver IP was still one of the temporary transition IPs that was now gone. Seems the extra delay with all the DNS timeouts was enough for the SSHD login process to time out. I set the correct DNS resolver IPs and SSH started working flawlessly.
Solution 3
I had a similar problem
With one user I could connect so I checked /etc/passwd. I saw this user could connect with bash, the other (not working) with fish
So I changed to bash and both worked.
Then I put it back to fish, and analysed my fish config and removed a line at the end that was added with byobu-enable. Then it worked. Then I reran byobu-enable and it works.
No idea what happened and it's a VERY specific case but I think I had the config file open while I ran byobu-enable and it messed things up
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ganjan
Updated on September 18, 2022Comments
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ganjan over 1 year
I am trying to run
ssh
on my computer so I can control it with my android phone. When I scan my local network withoverlook fing
at my phone I get that my computer is runningssh
at port 22. So I try to connect withconnectBot
I get:Linux linux 2.6.35-28-generic-pae #50-Ubuntu SMP Fri Mar 18 20:43:15 UTC 2011 i686 GNU/Linux Ubuntu 10.10 Welcome to Ubuntu! * Documentation: https://help.ubuntu.com/ 0 packages can be updated. 0 updates are security updates. Last login: Mon Apr 25 15:27:36 2011 from linux Connection to localhost closed.
Then a message: "Host has disconnected. Close session?"
When I run
ssh user@localhost
at the computer I get the same thing. Seems that ssh is setup incorrectly, I get a password prompt and information about the computer, but then the connection instantly close. Why?EDIT:
auth.log
:Apr 25 15:39:27 linux sshd[4932]: pam_sm_authenticate: Called Apr 25 15:39:27 linux sshd[4932]: pam_sm_authenticate: username = [user] Apr 25 15:39:27 linux sshd[4932]: pam_sm_authenticate: /home/user is already mounted Apr 25 15:39:27 linux sshd[4932]: Accepted password for user from ::1 port 48442 ssh2 Apr 25 15:39:27 linux sshd[4932]: pam_unix(sshd:session): session opened for user user by (uid=0) Apr 25 15:39:27 linux sshd[5079]: Received disconnect from ::1: 11: disconnected by user Apr 25 15:39:27 linux sshd[4932]: pam_unix(sshd:session): session closed for user user
ssh -vvv user@localhost
:user@linux:~$ ssh -vvv user@localhost OpenSSH_5.5p1 Debian-4ubuntu5, OpenSSL 0.9.8o 01 Jun 2010 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to localhost [::1] port 22. debug1: Connection established. debug1: identity file /home/user/.ssh/id_rsa type -1 debug1: identity file /home/user/.ssh/id_rsa-cert type -1 debug1: identity file /home/user/.ssh/id_dsa type -1 debug1: identity file /home/user/.ssh/id_dsa-cert type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_5.5p1 Debian-4ubuntu5 debug1: match: OpenSSH_5.5p1 Debian-4ubuntu5 pat OpenSSH* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-4ubuntu5 debug2: fd 3 setting O_NONBLOCK debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: [email protected],[email protected],ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,[email protected],zlib debug2: kex_parse_kexinit: none,[email protected],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-sha256,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-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected] debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,[email protected] debug2: kex_parse_kexinit: none,[email protected] debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: mac_setup: found hmac-md5 debug1: kex: server->client aes128-ctr hmac-md5 none debug2: mac_setup: found hmac-md5 debug1: kex: client->server aes128-ctr 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: 146/256 debug2: bits set: 513/1024 debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug3: check_host_in_hostfile: host localhost filename /home/user/.ssh/known_hosts debug3: check_host_in_hostfile: host localhost filename /home/user/.ssh/known_hosts debug3: check_host_in_hostfile: match line 1 debug1: Host 'localhost' is known and matches the RSA host key. debug1: Found key in /home/user/.ssh/known_hosts:1 debug2: bits set: 509/1024 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: Roaming not allowed by server debug1: SSH2_MSG_SERVICE_REQUEST sent debug2: service_accept: ssh-userauth debug1: SSH2_MSG_SERVICE_ACCEPT received debug2: key: /home/user/.ssh/id_rsa ((nil)) debug2: key: /home/user/.ssh/id_dsa ((nil)) debug1: Authentications that can continue: publickey,password debug3: start over, passed a different list publickey,password debug3: preferred gssapi-keyex,gssapi-with-mic,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/user/.ssh/id_rsa debug3: no such identity: /home/user/.ssh/id_rsa debug1: Trying private key: /home/user/.ssh/id_dsa debug3: no such identity: /home/user/.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 user@localhost's password: debug3: packet_send2: adding 64 (len 57 padlen 7 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: Requesting [email protected] debug1: Entering interactive session. debug2: callback start debug2: client_session2_setup: id 0 debug2: channel 0: request pty-req confirm 1 debug1: Sending environment. debug3: Ignored env ORBIT_SOCKETDIR debug3: Ignored env SSH_AGENT_PID debug3: Ignored env TERM debug3: Ignored env SHELL debug3: Ignored env XDG_SESSION_COOKIE debug3: Ignored env WINDOWID debug3: Ignored env GNOME_KEYRING_CONTROL debug3: Ignored env GTK_MODULES debug3: Ignored env USER debug3: Ignored env LS_COLORS debug3: Ignored env LIBGL_DRIVERS_PATH debug3: Ignored env SSH_AUTH_SOCK debug3: Ignored env DEFAULTS_PATH debug3: Ignored env SESSION_MANAGER debug3: Ignored env USERNAME debug3: Ignored env XDG_CONFIG_DIRS debug3: Ignored env DESKTOP_SESSION debug3: Ignored env LIBGL_ALWAYS_INDIRECT debug3: Ignored env PATH debug3: Ignored env PWD debug3: Ignored env GDM_KEYBOARD_LAYOUT debug1: Sending env LANG = en_US.UTF-8 debug2: channel 0: request env confirm 0 debug3: Ignored env GNOME_KEYRING_PID debug3: Ignored env MANDATORY_PATH debug3: Ignored env GDM_LANG debug3: Ignored env GDMSESSION debug3: Ignored env SHLVL debug3: Ignored env HOME debug3: Ignored env GNOME_DESKTOP_SESSION_ID debug3: Ignored env LOGNAME debug3: Ignored env XDG_DATA_DIRS debug3: Ignored env DBUS_SESSION_BUS_ADDRESS debug3: Ignored env LESSOPEN debug3: Ignored env WINDOWPATH debug3: Ignored env DISPLAY debug3: Ignored env LESSCLOSE debug3: Ignored env XAUTHORITY debug3: Ignored env COLORTERM debug3: Ignored env _ 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 2097152 debug2: channel_input_status_confirm: type 99 id 0 debug2: shell request accepted on channel 0 Linux linux 2.6.35-28-generic-pae #50-Ubuntu SMP Fri Mar 18 20:43:15 UTC 2011 i686 GNU/Linux Ubuntu 10.10 Welcome to Ubuntu! * Documentation: https://help.ubuntu.com/ Last login: Mon Apr 25 15:39:27 2011 from linux debug1: client_input_channel_req: channel 0 rtype exit-status reply 0 debug1: client_input_channel_req: channel 0 rtype [email protected] reply 0 debug2: channel 0: rcvd eow debug2: channel 0: close_read debug2: channel 0: input open -> closed 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 debug2: channel 0: rcvd close debug3: channel 0: will not send data after close 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 debug3: channel 0: status: The following connections are open: #0 client-session (t4 r0 i3/0 o3/0 fd -1/-1 cc -1) debug3: channel 0: close_fds r -1 w -1 e 6 Connection to localhost closed. Transferred: sent 1800, received 2232 bytes, in 0.4 seconds Bytes per second: sent 4972.2, received 6165.5 debug1: Exit status 0 user@linux:~$
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binfalse about 13 yearstry to connect with
ssh -vvv user@whatever
, and also take a look into your/var/log/auth.log
. If you still can't see any errors please provide the output of the ssh command and the interesting lines of the log file. -
Tier2helpdesk over 6 yearsIn your ConnectBot host settings, have you enabled Start a shell session?
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NuSkooler over 4 yearsI had this same issue today logging into a CentOS 7 machine. I've have byobu (via byobu-enable) my default for a while but it just stopped. chsh -s from another account and/or edit the ~/.config/fish/config.fish to remove this and it works again. Very odd.