unable to connect no matter what

[felixtech-msp]

I am completely unable to connect to the server with neither SFTP or SCP. There is no useful log output, even in DEBUG3 log level.
Authentication is successful but then establishing a session is impossible and will always fail. The server doesn't respond anymore after authenticating.

docker-compose.yml

  teleporter:
    image: atmoz/sftp:alpine
    restart: always
    ports:
      - "2222:22/tcp"
    volumes:
      - teleporter:/home/user/backups:ro
      - teleporter-config:/etc/ssh
    command: user:pass:::backups
    network_mode: bridge

Log output after successful authentication:

Accepted password for user from 192.168.0.2 port 51034 ssh2
debug1: monitor_child_preauth: user user authenticated by privileged process
debug3: mm_get_keystate: Waiting for new keys
debug3: mm_request_receive_expect: entering, type 26
debug3: mm_request_receive: entering
debug3: mm_get_keystate: GOT new keys
debug3: mm_auth_password: user authenticated [preauth]
debug3: user_specific_delay: user specific delay 0.000ms [preauth]
debug3: ensure_minimum_time_since: elapsed 19.212ms, delaying 15.619ms (requested 8.708ms) [preauth]
debug3: send packet: type 52 [preauth]
debug3: mm_request_send: entering, type 26 [preauth]
debug3: mm_send_keystate: Finished sending state [preauth]
debug1: monitor_read_log: child log fd closed
debug3: ssh_sandbox_parent_finish: finished
User child is on pid 25
debug3: safely_chroot: checking '/'
debug3: safely_chroot: checking '/home/'
debug3: safely_chroot: checking '/home/user'
Changed root directory to "/home/user"
debug1: permanently_set_uid: 1000/100
debug3: monitor_apply_keystate: packet_set_state
debug2: ssh_set_newkeys: mode 0
debug1: rekey in after 4294967296 blocks
debug2: ssh_set_newkeys: mode 1
debug1: rekey out after 4294967296 blocks
debug1: ssh_packet_set_postauth: called
debug3: ssh_packet_set_state: done
debug3: notify_hostkeys: key 0: ssh-ed25519 SHA256:R8fUklYxWuLSfb+VbQsqQ8glzwUZOQ0duDrAtpQ2Fr0
debug3: notify_hostkeys: key 1: ssh-rsa SHA256:kFSxlPt7gupO2Msc0HFOH9fFIO1GEhScZpoinBHyro4
debug3: notify_hostkeys: sent 2 hostkeys
debug3: send packet: type 80
debug1: active: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
debug1: Entering interactive session for SSH2.
debug1: server_init_dispatch
debug3: receive packet: type 90
debug1: server_input_channel_open: ctype session rchan 256 win 2147483647 max 16384
debug1: input_session_request
debug1: channel 0: new session [server-session] (inactive timeout: 0)
debug2: session_new: allocate (allocated 0 max 10)
debug3: session_unused: session id 0 unused
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
debug3: send packet: type 91
debug3: receive packet: type 98
debug1: server_input_channel_req: channel 0 request [email protected] reply 0
debug1: session_by_channel: session 0 channel 0
debug1: session_input_channel_req: session 0 req [email protected]
debug3: receive packet: type 98
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
debug2: channel_set_xtype: labeled channel 0 as session:shell (inactive timeout 0)
Starting session: forced-command (config) 'internal-sftp' for user from 192.168.0.2 port 51034 id 0
debug2: fd 4 setting TCP_NODELAY
debug3: set_sock_tos: set socket 4 IP_TOS 0x20
debug2: fd 8 setting O_NONBLOCK
debug2: fd 7 setting O_NONBLOCK
debug2: fd 10 setting O_NONBLOCK
debug3: send packet: type 99

[nitwhiz]

sounds like #341?

does adding

ulimits:
  nofile:
    soft: 65536
    hard: 65536

to the service help?

[vagkaefer]

Exact same situation in here, i tried a lot of things, the ulimits solved! Thank you