After upgrading from openssh7.3 to openssh7.5p1. I see following errors.
ssh_dispatch_run_fatal: Connection to 127.0.0.1 port 8002: message authentication code incorrect
System details - x86_64 x86_64 x86_64 GNU/Linux
Unfortunately there is insufficient info here to even guess. What distro/version are you using? Is the version of OpenSSH provided by the distro vendor or are you compiling the source available at openssh.com? What's listening on port 8002? That's not a standard ssh port. Please create a debug log "ssh -vvv whatever" and use "Add an attachment" to attach that to this bug.
I compiled the source available from openssh.com https://mirrors.evowise.com/pub/OpenBSD/OpenSSH/portable/openssh-7.5p1.tar.gz
You answered only one of about six questions and didn't provide the log that might provide more information.
I use following command: ssh -o StrictHostKeyChecking=no -o Compression=yes -o ServerAliveInterval=5 -o ServerAliveCountMax=6 -o StreamLocalBindMask=0111 -o StreamLocalBindUnlink=yes -o ControlBindMask=0111 -o ControlAllowUsers=* -o HostKeyAlgorithms=+ssh-dss -i /home/cluster/.ssh/identity -L [/var/cluster/mysql/618005.sock]:[/var/lib/mysql/mysql.sock] -T -M -S /var/cluster/ssh/618005.sock -p 8002 cluster@127.0.0.1 /bin/cat OpenSSH_7.5p1, OpenSSL 1.0.2l 25 May 2017 debug1: Reading configuration data /root/.ssh/config debug1: Reading configuration data /home/spyware/code/firmware/current/etc/ssh/ssh_config debug2: resolving "127.0.0.1" port 8002 debug2: ssh_connect_direct: needpriv 0 debug1: Connecting to 127.0.0.1 [127.0.0.1] port 8002. debug1: connect to address 127.0.0.1 port 8002: Connection refused ssh: connect to host 127.0.0.1 port 8002: Connection refused
That debug log does not correspond to the error you are seeking help with (and you didn't use "Add an attachment" as requested) and you *still* haven't answered most of the questions I asked in comment #3.
Apologize as it too some time to collect logs. Please find it below. SSH Logs: OpenSSH_7.5p1, OpenSSL 1.0.2l 25 May 2017 debug1: Reading configuration data /home/spyware/code/firmware/current/etc/ssh/ssh_config debug2: resolving "127.0.0.1" port 8002 debug2: ssh_connect_direct: needpriv 0 debug1: Connecting to 127.0.0.1 [127.0.0.1] port 8002. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /home/cluster/.ssh/identity type 2 debug1: key_load_public: No such file or directory debug1: identity file /home/cluster/.ssh/identity-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_7.5 debug1: Remote protocol version 2.0, remote software version Barracuda debug1: no match: Barracuda debug2: fd 3 setting O_NONBLOCK debug1: Authenticating to 127.0.0.1:8002 as 'cluster' debug3: send packet: type 20 debug1: SSH2_MSG_KEXINIT sent Bad packet length 1835101741. Sshd logs: debug1: Bind to port 8002 on 127.0.0.1. Server listening on 127.0.0.1 port 8002. debug3: fd 4 is not O_NONBLOCK debug1: Server will not fork when running in debugging mode. debug3: send_rexec_state: entering fd = 7 config len 209 debug3: ssh_msg_send: type 0 debug3: send_rexec_state: done debug1: rexec start in 4 out 4 newsock 4 pipe -1 sock 7 debug1: inetd sockets after dupping: 3, 3 Connection from 127.0.0.1 port 45473 on 127.0.0.1 port 8002 debug1: Client protocol version 2.0; client software version OpenSSH_7.5 debug1: match: OpenSSH_7.5 pat OpenSSH* compat 0x04000000 debug1: Local version string BCP-2.0-Barracuda debug1: Enabling compatibility mode for protocol 2.0 debug2: fd 3 setting O_NONBLOCK debug3: ssh_sandbox_init: preparing rlimit sandbox debug2: Network child is on pid 10214 debug3: preauth child monitor started debug3: privsep user:group 71:71 [preauth] debug1: permanently_set_uid: 71/71 [preauth] debug3: list_hostkey_types: ssh-dss key not permitted by HostkeyAlgorithms [preauth] debug1: list_hostkey_types: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519 [preauth] debug3: send packet: type 20 [preauth] debug1: SSH2_MSG_KEXINIT sent [preauth] debug3: receive packet: type 20 [preauth] debug1: SSH2_MSG_KEXINIT received [preauth] debug2: local server KEXINIT proposal [preauth] debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@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-group14-sha256,diffie-hellman-group14-sha1 [preauth] debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519 [preauth] debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com [preauth] debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com [preauth] debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1 [preauth] debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1 [preauth] debug2: compression ctos: none,zlib@openssh.com [preauth] debug2: compression stoc: none,zlib@openssh.com [preauth] debug2: languages ctos: [preauth] debug2: languages stoc: [preauth] debug2: first_kex_follows 0 [preauth] debug2: reserved 0 [preauth] debug2: peer client KEXINIT proposal [preauth] debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@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 [preauth] debug2: host key algorithms: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-dss [preauth] debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc [preauth] debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com,aes128-cbc,aes192-cbc,aes256-cbc [preauth] debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1 [preauth] debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1 [preauth] debug2: compression ctos: zlib@openssh.com,zlib,none [preauth] debug2: compression stoc: zlib@openssh.com,zlib,none [preauth] debug2: languages ctos: [preauth] debug2: languages stoc: [preauth] debug2: first_kex_follows 0 [preauth] debug2: reserved 0 [preauth] debug1: kex: algorithm: curve25519-sha256 [preauth] debug1: kex: host key algorithm: ecdsa-sha2-nistp256 [preauth] debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: zlib@openssh.com [preauth] debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: <implicit> compression: zlib@openssh.com [preauth] debug1: expecting SSH2_MSG_KEX_ECDH_INIT [preauth] Connection closed by 127.0.0.1 port 45473 [preauth] debug1: do_cleanup [preauth] debug1: monitor_read_log: child log fd closed debug3: mm_request_receive entering debug1: do_cleanup debug1: Killing privsep child 10214
Come on. Darren asked you multiple times to attach the logs rather than pasting them into the bug and you've ignored him again. If you expect us to debug your problem for free then you can at least read and follow what we ask. Here's your problem: debug1: Local version string BCP-2.0-Barracuda Your server is sending garbage to the client and disconnecting. The server looks it is dervied from OpenSSH, but it isn't OpenSSH. You need to follow up with whomever gave/sold it to you. There's nothing we can do to fix it.
Close all resolved bugs after release of OpenSSH 7.7.