openssh unix dev - Aug 2016 - [Portable OpenSSH] hang up during login after OpenSSH 7.3 upgrade

Hello to everyone, and thank for your job.


I am reporting here about a problem I am experiencing with portable SSH client,
version 7.3p1.
My client is an Archlinux system.
I am connecting to an Ubuntu server, which provides SSH with some patches (see
below).
It worked until the upgrade to 7.3p1.

This is the produced debug output.

Command line: ssh -v -v -v -v -v -v username at 10.196.37.5

OpenSSH_7.3p1, OpenSSL 1.0.2h  3 May 2016
debug1: Reading configuration data /home/mrkiko/.ssh/config
debug1: /home/mrkiko/.ssh/config line 4: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: auto-mux: Trying existing master
debug1: Control socket
"/home/mrkiko/.ssh/controlmasters/ffcb7b290d3be704cb5460c2430449dc7c74f50c"
does not exist
debug2: resolving "10.196.37.5" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 10.196.37.5 [10.196.37.5] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.3
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.7p1
Ubuntu-5ubuntu1.4
debug1: match: OpenSSH_6.7p1 Ubuntu-5ubuntu1.4 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 10.196.37.5:22 as 'username'
debug3: hostkeys_foreach: reading file "/home/mrkiko/.ssh/known_hosts"
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256 at
libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ecdsa-sha2-nistp256-cert-v01 at
openssh.com,ecdsa-sha2-nistp384-cert-v01 at
openssh.com,ecdsa-sha2-nistp521-cert-v01 at openssh.com,ssh-ed25519-cert-v01 at
openssh.com,ssh-rsa-cert-v01 at
openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305 at
openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at
openssh.com,aes256-gcm at openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: ciphers stoc: chacha20-poly1305 at
openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at
openssh.com,aes256-gcm at openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: MACs ctos: umac-64-etm at openssh.com,umac-128-etm at
openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at
openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at
openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm at openssh.com,umac-128-etm at
openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at
openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at
openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib at openssh.com,zlib
debug2: compression stoc: none,zlib at openssh.com,zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256 at
libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at
openssh.com,aes256-gcm at openssh.com,chacha20-poly1305 at openssh.com
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at
openssh.com,aes256-gcm at openssh.com,chacha20-poly1305 at openssh.com
debug2: MACs ctos: umac-64-etm at openssh.com,umac-128-etm at
openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at
openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at
openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm at openssh.com,umac-128-etm at
openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at
openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at
openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib at openssh.com
debug2: compression stoc: none,zlib at openssh.com
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: curve25519-sha256 at libssh.org
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305 at openssh.com MAC:
<implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305 at openssh.com MAC:
<implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
<hangs here>


But dbclient (from Dropbear) works instead with the same setup (and server),
asking me the password as expected.

On the server side, we have an Ubuntu 15.04 Linux sitribution, with ssh
reporting as version
OpenSSH_6.7p1 Ubuntu-5ubuntu1.4

The number of patches Ubuntu applies to this package is relatively high I would 
say: and I know this doesn't help. What made me think it's still worth 
reporting, is:
- Openssh 7.2 worked fine with this server
- Dropbear SSH client does work
- the software does wait indefinitely, not reporting any error or message
   (which I think would be desireable).

With SSH client 7.2, the debug output is as follows, when connecting to the same
server:

Command line: ssh -v -v -v -v -v -v -v username at 10.196.37.5
OpenSSH_7.2p2, OpenSSL 1.0.2h  3 May 2016
debug1: Reading configuration data /home/mrkiko/.ssh/config
debug1: /home/mrkiko/.ssh/config line 4: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: auto-mux: Trying existing master
debug1: Control socket
"/home/mrkiko/.ssh/controlmasters/ffcb7b290d3be704cb5460c2430449dc7c74f50c"
does not exist
debug2: resolving "10.196.37.5" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 10.196.37.5 [10.196.37.5] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/mrkiko/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.7p1
Ubuntu-5ubuntu1.4
debug1: match: OpenSSH_6.7p1 Ubuntu-5ubuntu1.4 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 10.196.37.5:22 as 'username'
debug3: hostkeys_foreach: reading file "/home/mrkiko/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file
/home/mrkiko/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from 10.196.37.5
debug3: order_hostkeyalgs: prefer hostkeyalgs: ecdsa-sha2-nistp256-cert-v01 at
openssh.com,ecdsa-sha2-nistp384-cert-v01 at
openssh.com,ecdsa-sha2-nistp521-cert-v01 at
openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256 at
libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: ecdsa-sha2-nistp256-cert-v01 at
openssh.com,ecdsa-sha2-nistp384-cert-v01 at
openssh.com,ecdsa-sha2-nistp521-cert-v01 at
openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519-cert-v01
at openssh.com,ssh-rsa-cert-v01 at
openssh.com,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: chacha20-poly1305 at
openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at
openssh.com,aes256-gcm at openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: ciphers stoc: chacha20-poly1305 at
openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at
openssh.com,aes256-gcm at openssh.com,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc
debug2: MACs ctos: umac-64-etm at openssh.com,umac-128-etm at
openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at
openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at
openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm at openssh.com,umac-128-etm at
openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at
openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at
openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib at openssh.com,zlib
debug2: compression stoc: none,zlib at openssh.com,zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256 at
libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at
openssh.com,aes256-gcm at openssh.com,chacha20-poly1305 at openssh.com
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm at
openssh.com,aes256-gcm at openssh.com,chacha20-poly1305 at openssh.com
debug2: MACs ctos: umac-64-etm at openssh.com,umac-128-etm at
openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at
openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at
openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm at openssh.com,umac-128-etm at
openssh.com,hmac-sha2-256-etm at openssh.com,hmac-sha2-512-etm at
openssh.com,hmac-sha1-etm at openssh.com,umac-64 at openssh.com,umac-128 at
openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib at openssh.com
debug2: compression stoc: none,zlib at openssh.com
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: curve25519-sha256 at libssh.org
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305 at openssh.com MAC:
<implicit> compression: none
debug1: kex: client->server cipher: chacha20-poly1305 at openssh.com MAC:
<implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256
SHA256:yo//ykmurZf9IJ/ORTP9Ep3wheYf1u2xXXdV+4uAH6M
debug3: hostkeys_foreach: reading file "/home/mrkiko/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file
/home/mrkiko/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from 10.196.37.5
debug1: Host '10.196.37.5' is known and matches the ECDSA host key.
debug1: Found key in /home/mrkiko/.ssh/known_hosts:1
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS received
debug1: pubkey_prepare: ssh_get_authentication_socket: No such file or directory
debug2: key: /home/mrkiko/.ssh/id_rsa ((nil))
debug2: key: /home/mrkiko/.ssh/id_dsa ((nil))
debug2: key: /home/mrkiko/.ssh/id_ecdsa ((nil))
debug2: key: /home/mrkiko/.ssh/id_ed25519 ((nil))
debug3: send packet: type 5
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
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/mrkiko/.ssh/id_rsa
debug3: no such identity: /home/mrkiko/.ssh/id_rsa: No such file or directory
debug1: Trying private key: /home/mrkiko/.ssh/id_dsa
debug3: no such identity: /home/mrkiko/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /home/mrkiko/.ssh/id_ecdsa
debug3: no such identity: /home/mrkiko/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /home/mrkiko/.ssh/id_ed25519
debug3: no such identity: /home/mrkiko/.ssh/id_ed25519: No such file or
directory
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
username at 10.196.37.5's password: 
debug3: send packet: type 50
debug2: we sent a password packet, wait for reply
debug3: receive packet: type 52
debug1: Authentication succeeded (password).
Authenticated to 10.196.37.5 ([10.196.37.5]:22).
debug1: setting up multiplex master socket
debug3: muxserver_listen: temporary control path
/home/mrkiko/.ssh/controlmasters/ffcb7b290d3be704cb5460c2430449dc7c74f50c.UvIEO9zBRNphS1SE
debug2: fd 4 setting O_NONBLOCK
debug3: fd 4 is O_NONBLOCK
debug3: fd 4 is O_NONBLOCK
debug1: channel 0: new
[/home/mrkiko/.ssh/controlmasters/ffcb7b290d3be704cb5460c2430449dc7c74f50c]
debug3: muxserver_listen: mux listener channel 0 fd 4
debug2: fd 3 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x08
debug1: control_persist_detach: backgrounding master process
debug2: control_persist_detach: background process is 1259
debug2: fd 4 setting O_NONBLOCK
debug1: forking to background
debug1: Entering interactive session.
debug1: pledge: id
debug2: set_control_persist_exit_time: schedule exit in 60 seconds
debug1: multiplexing control connection
debug2: fd 5 setting O_NONBLOCK
debug3: fd 5 is O_NONBLOCK
debug1: channel 1: new [mux-control]
debug3: channel_post_mux_listener: new mux channel 1 fd 5
debug3: mux_master_read_cb: channel 1: hello sent
debug2: set_control_persist_exit_time: cancel scheduled exit
debug3: mux_master_read_cb: channel 1 packet type 0x00000001 len 4
debug2: process_mux_master_hello: channel 1 slave version 4
debug2: mux_client_hello_exchange: master version 4
debug3: mux_client_forwards: request forwardings: 0 local, 0 remote
debug3: mux_client_request_session: entering
debug3: mux_client_request_alive: entering
debug3: mux_master_read_cb: channel 1 packet type 0x10000004 len 4
debug2: process_mux_alive_check: channel 1: alive check
debug3: mux_client_request_alive: done pid = 1261
debug3: mux_client_request_session: session request sent
debug3: mux_master_read_cb: channel 1 packet type 0x10000002 len 41
debug2: process_mux_new_session: channel 1: request tty 1, X 0, agent 0, subsys
0, term "linux", cmd "", env 0
debug3: process_mux_new_session: got fds stdin 6, stdout 7, stderr 8
debug1: channel 2: new [client-session]
debug2: process_mux_new_session: channel_new: 2 linked to control channel 1
debug2: channel 2: send open
debug3: send packet: type 90
debug3: receive packet: type 91
debug2: callback start
debug2: client_session2_setup: id 2
debug2: channel 2: request pty-req confirm 1
debug3: send packet: type 98
debug2: channel 2: request shell confirm 1
debug3: send packet: type 98
debug3: mux_session_confirm: sending success reply
debug2: callback done
debug2: channel 2: open confirm rwindow 0 rmax 32768
debug1: mux_client_request_session: master session id: 2
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 2
debug2: PTY allocation request accepted on channel 2
debug2: channel 2: rcvd adjust 2097152
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 2
debug2: shell request accepted on channel 2
Welcome to Ubuntu 15.04 (GNU/Linux 3.19.0-65-generic x86_64)

  * Documentation:  https://help.ubuntu.com/

Your Ubuntu release is not supported anymore.
For upgrade information, please visit:
http://www.ubuntu.com/releaseendoflife

New release '15.10' available.
Run 'do-release-upgrade' to upgrade to it.

*** System restart required ***
Last login: Wed Aug 17 05:19:02 2016 from 10.31.0.197
<shell prompt>

debug3: receive packet: type 96
debug2: channel 2: rcvd eof
debug2: channel 2: output open -> drain
debug2: channel 2: obuf empty
debug2: channel 2: close_write
debug2: channel 2: output drain -> closed
debug3: receive packet: type 98
debug1: client_input_channel_req: channel 2 rtype exit-status reply 0
debug3: mux_exit_message: channel 2: exit message, exitval 0
debug3: receive packet: type 98
debug1: client_input_channel_req: channel 2 rtype eow at openssh.com reply 0
debug2: channel 2: rcvd eow
debug2: channel 2: close_read
debug2: channel 2: input open -> closed
debug3: receive packet: type 97
debug2: channel 2: rcvd close
debug3: channel 2: will not send data after close
debug2: channel 2: send close
debug3: send packet: type 97
debug2: channel 2: is dead
debug2: channel 2: gc: notify user
debug3: mux_master_session_cleanup_cb: entering for channel 2
debug2: channel 1: rcvd close
debug2: channel 1: output open -> drain
debug2: channel 1: close_read
debug2: channel 1: input open -> closed
debug2: channel 2: gc: user detached
debug2: channel 2: is dead
debug2: channel 2: garbage collecting
debug1: channel 2: free: client-session, nchannels 3
debug3: channel 2: status: The following connections are open:
   #2 client-session (t4 r0 i3/0 o3/0 fd -1/-1 cc -1)

debug2: channel 1: obuf empty
debug2: channel 1: close_write
debug2: channel 1: output drain -> closed
debug2: channel 1: is dead (local)
debug2: channel 1: gc: notify user
debug3: mux_master_control_cleanup_cb: entering for channel 1
debug2: channel 1: gc: user detached
debug2: channel 1: is dead (local)
debug2: channel 1: garbage collecting
debug1: channel 1: free: mux-control, nchannels 2
debug3: channel 1: status: The following connections are open:

debug2: set_control_persist_exit_time: schedule exit in 60 seconds
debug3: mux_client_read_packet: read header failed: Broken pipe
debug2: Received exit status from master 0
Asking ssh to stop the mux process: ssh -v -v -v -v -v -v -v username at
10.196.37.55 -O stop
OpenSSH_7.2p2, OpenSSL 1.0.2h  3 May 2016
debug1: Reading configuration data /home/mrkiko/.ssh/config
debug1: /home/mrkiko/.ssh/config line 4: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: auto-mux: Trying existing master
debug1: multiplexing control connection
debug2: fd 5 setting O_NONBLOCK
debug3: fd 5 is O_NONBLOCK
debug1: channel 1: new [mux-control]
debug3: channel_post_mux_listener: new mux channel 1 fd 5
debug3: mux_master_read_cb: channel 1: hello sent
debug2: set_control_persist_exit_time: cancel scheduled exit
debug2: fd 3 setting O_NONBLOCK
debug3: mux_master_read_cb: channel 1 packet type 0x00000001 len 4
debug2: process_mux_master_hello: channel 1 slave version 4
debug2: mux_client_hello_exchange: master version 4
debug3: mux_client_request_stop_listening: entering
debug3: mux_master_read_cb: channel 1 packet type 0x10000009 len 4
debug1: process_mux_stop_listening: channel 1: stop listening
debug1: channel 0: free:
/home/mrkiko/.ssh/controlmasters/ffcb7b290d3be704cb5460c2430449dc7c74f50c,
nchannels 2
debug3: channel 0: status: The following connections are open:

Stop listening request sent.
debug2: channel 1: ctl read<=0 rfd 5 len 0
debug2: channel 1: read failed
debug2: channel 1: close_read
debug2: channel 1: input open -> drain
debug2: channel 1: ibuf empty
debug2: channel 1: input drain -> closed
debug2: channel 1: rcvd close
debug2: channel 1: output open -> drain
debug2: channel 1: obuf empty
debug2: channel 1: close_write
debug2: channel 1: output drain -> closed
debug2: channel 1: is dead (local)
debug2: channel 1: gc: notify user
debug3: mux_master_control_cleanup_cb: entering for channel 1
debug2: channel 1: gc: user detached
debug2: channel 1: is dead (local)
debug2: channel 1: garbage collecting
debug1: channel 1: free: mux-control, nchannels 1
debug3: channel 1: status: The following connections are open:

debug3: send packet: type 1
debug3: fd 0 is not O_NONBLOCK
debug3: fd 1 is not O_NONBLOCK
Transferred: sent 2076, received 2200 bytes, in 8.9 seconds
Bytes per second: sent 232.9, received 246.8
debug1: Exit status -1

thanks you a lot guys for your work and help,
Enrico

Sorry... as a side note: I am not subscribed. So keep me in CC, please.
Thanks again a lot for your work,
Enrico

On Wed, Aug 17, 2016 at 1:29 PM, Enrico Mioso <mrkiko.rs at gmail.com>
wrote:
[....]
> debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
> <hangs here>
Smells like a path MTU black hole.  See
http://www.snailbook.com/faq/mtu-mismatch.auto.html for some
suggestions.
> But dbclient (from Dropbear) works instead with the same setup (and
server),
> asking me the password as expected.
dbclient supports fewer algorithms and its network traffic is
correspondingly smaller, which makes it less likely to trip the
threshold (same for older opensshs).

-- 
Darren Tucker (dtucker at zip.com.au)
GPG key 11EAA6FA / A86E 3E07 5B19 5880 E860  37F4 9357 ECEF 11EA A6FA (new)
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.

Yeah, I think this can be the reason.
Thank you very much guys.
Enrico

Ok, now it works infact. it was a MTU problem.
Thanks you all again,
Enrico