I have a ubuntu linux server hosted on Amazon EC2. There are more than 3000 linux users in the system, such as user_1, user_2, etc.
Surprisingly, users up to user_2685 can log in via ssh to the server. Not further.
I changed LogLevel to DEBUG3 in / etc / ssh / sshd _config. Insert relevant content.
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18879]: debug1: Allocating pty.
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18879]: debug3: mm_request_send entering: type 26
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18879]: debug3: mm_pty_allocate: waiting for MONITOR_ANS_PTY
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18879]: debug3: mm_request_receive_expect entering: type 27
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18879]: debug3: mm_request_receive entering
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18802]: debug3: mm_request_receive entering
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18802]: debug3: monitor_read: checking request 26
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18802]: debug3: mm_answer_pty entering
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18802]: debug2: session_new: allocate (allocated 0 max 10)
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18802]: debug3: session_unused: session id 0 unused
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18802]: debug1: session_new: session 0
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18802]: debug1: SELinux support disabled
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18879]: debug1: do_cleanup
Apr 18 10:18:00 domU-12-31-39-01-86-0C sshd [18879]: debug3: PAM: sshpam_thread_cleanup entering
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug1: Allocating pty.
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug3: mm_request_send entering: type 26
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug3: mm_pty_allocate: waiting for MONITOR_ANS_PTY
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug3: mm_request_receive_expect entering: type 27
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug3: mm_request_receive entering
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18880]: debug3: mm_request_receive entering
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18880]: debug3: monitor_read: checking request 26
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18880]: debug3: mm_answer_pty entering
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18880]: debug2: session_new: allocate (allocated 0 max 10)
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18880]: debug3: session_unused: session id 0 unused
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18880]: debug1: session_new: session 0
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18880]: debug1: SELinux support disabled
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18880]: debug3: mm_request_send entering: type 27
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18880]: debug3: mm_answer_pty: tty / dev / pts / 37 ptyfd 4
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug1: session_pty_req: session 0 alloc / dev / pts / 37
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug1: Ignoring unsupported tty mode opcode 11 (0xb)
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug1: Ignoring unsupported tty mode opcode 17 (0x11)
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug1: server_input_channel_req: channel 0 request shell reply 1
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug1: session_by_channel: session 0 channel 0
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug1: session_input_channel_req: session 0 req shell
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug2: fd 3 setting TCP_NODELAY
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug2: channel 0: rfd 9 isatty
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug2: fd 9 setting O_NONBLOCK
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18957]: debug3: fd 7 is O_NONBLOCK
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18958]: debug1: Setting controlling tty using TIOCSCTTY.
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18958]: debug3: Copy environment: PATH = / usr / local / sbin: / usr / local / bin: / usr / sbin : / usr / bin: / sbin: / bin: / usr / games
Apr 18 10:20:07 domU-12-31-39-01-86-0C sshd [18958]: debug3: Copy environment: LANG = en_US.UTF-8
Apr 18 10:20:07 domU-12-31-39-01-86-0C jk_chrootsh [18958]: now entering jail / opt / users-rails-apps for user user_1 (1001) with arguments
Update 1:
The above dumps from /var/log/auth.log on the server. The following are dumps on the client. Just place the corresponding dump part which is different
Successful login
debug2: channel 0: request shell confirm 1
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
Failed login
debug2: channel 0: request shell confirm 1
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug1: channel 0: free: client-session, nchannels 1
debug3: channel 0: status: The following connections are open:
# 0 client-session (t4 r0 i0 / 0 o0 / 0 fd 4/5 cc -1)
Connection to www.codelearn.org closed by remote host.
Connection to www.codelearn.org closed.
Transferred: sent 2488, received 1472 bytes, in 0.8 seconds
Bytes per second: sent 3043.4, received 1800.6
debug1: Exit status -1
OS: Ubuntu exact 12.04
Openssh server: OpenSSH_5.9p1 Debian-5ubuntu1.1, OpenSSL 1.0.1 14 Mar 2012
SSH client: it doesn't matter since I tried to use ubuntu as well as Mac and the behavior is the same.
Update 2:
Btw is not a problem with PAM, since I can do su user_3000 and a new user logs in and receives PTY.
Also does ssh without a PTY request ssh -T user_3000@www.codelearn.org registers the user. But he stops sending messages and the invitation does not appear. This is probably because the invitation was not requested first.