Thanks for your suggestion! It seems to have gone a little further this time, but isn't accepting the key and is failing back on password-based auth. We're double-checking that the public key was correctly configured with the account, and also trying a DSA key to see if it behaves differently. Is there anything you'd suggest we look at or try at this point, and thank you very much for your input. [root@client ~]# sftp -vvv -oKEXAlgorithms=diffie-hellman-group14-sha1 -oport=32 SOMEUSER@xxxxxxxxxxxx.server OpenSSH_7.2p2, OpenSSL 1.0.2h 3 May 2016 debug1: Reading configuration data /etc/ssh/ssh_config debug2: resolving "IBM.SFG.SFTP.server" port 32 debug2: ssh_connect_direct: needpriv 0 debug1: Connecting to IBM.SFG.SFTP.server [1.2.3.4] port 32. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /root/.ssh/id_rsa type 1 debug1: key_load_public: No such file or directory debug1: identity file /root/.ssh/id_rsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /root/.ssh/id_dsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /root/.ssh/id_dsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /root/.ssh/id_ecdsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /root/.ssh/id_ecdsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /root/.ssh/id_ed25519 type -1 debug1: key_load_public: No such file or directory debug1: identity file /root/.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 Welcome To Ceridian debug1: no match: Welcome To Ceridian debug2: fd 3 setting O_NONBLOCK debug1: Authenticating to IBM.SFG.SFTP.server:32 as 'SOMEUSER' debug3: put_host_port: [IBM.SFG.SFTP.server]:32 debug3: hostkeys_foreach: reading file "/root/.ssh/known_hosts" debug3: record_hostkey: found key type RSA in file /root/.ssh/known_hosts:57 debug3: load_hostkeys: loaded 1 keys from [IBM.SFG.SFTP.server]:32 debug3: order_hostkeyalgs: prefer hostkeyalgs: ssh-rsa-cert-v01@xxxxxxxxxxx,rsa-sha2-512,rsa-sha2-256,ssh-rsa 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: diffie-hellman-group14-sha1,ext-info-c debug2: host key algorithms: ssh-rsa-cert-v01@xxxxxxxxxxx,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256-cert-v01@xxxxxxxxxxx,ecdsa-sha2-nistp384-cert-v01@xxxxxxxxxxx,ecdsa-sha2-nistp521-cert-v01@xxxxxxxxxxx,ssh-ed25519-cert-v01@xxxxxxxxxxx,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519 debug2: ciphers ctos: chacha20-poly1305@xxxxxxxxxxx,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@xxxxxxxxxxx,aes256-gcm@xxxxxxxxxxx,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc debug2: ciphers stoc: chacha20-poly1305@xxxxxxxxxxx,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@xxxxxxxxxxx,aes256-gcm@xxxxxxxxxxx,aes128-cbc,aes192-cbc,aes256-cbc,3des-cbc debug2: MACs ctos: umac-64-etm@xxxxxxxxxxx,umac-128-etm@xxxxxxxxxxx,hmac-sha2-256-etm@xxxxxxxxxxx,hmac-sha2-512-etm@xxxxxxxxxxx,hmac-sha1-etm@xxxxxxxxxxx,umac-64@xxxxxxxxxxx,umac-128@xxxxxxxxxxx,hmac-sha2-256,hmac-sha2-512,hmac-sha1 debug2: MACs stoc: umac-64-etm@xxxxxxxxxxx,umac-128-etm@xxxxxxxxxxx,hmac-sha2-256-etm@xxxxxxxxxxx,hmac-sha2-512-etm@xxxxxxxxxxx,hmac-sha1-etm@xxxxxxxxxxx,umac-64@xxxxxxxxxxx,umac-128@xxxxxxxxxxx,hmac-sha2-256,hmac-sha2-512,hmac-sha1 debug2: compression ctos: none,zlib@xxxxxxxxxxx,zlib debug2: compression stoc: none,zlib@xxxxxxxxxxx,zlib debug2: languages ctos: debug2: languages stoc: debug2: first_kex_follows 0 debug2: reserved 0 debug2: peer server KEXINIT proposal debug2: KEX algorithms: diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521 debug2: host key algorithms: ssh-rsa debug2: ciphers ctos: aes256-cbc,aes192-cbc debug2: ciphers stoc: aes256-cbc,aes192-cbc debug2: MACs ctos: hmac-sha1 debug2: MACs stoc: hmac-sha1 debug2: compression ctos: none debug2: compression stoc: none debug2: languages ctos: debug2: languages stoc: debug2: first_kex_follows 0 debug2: reserved 0 debug1: kex: algorithm: diffie-hellman-group14-sha1 debug1: kex: host key algorithm: ssh-rsa debug1: kex: server->client cipher: aes192-cbc MAC: hmac-sha1 compression: none debug1: kex: client->server cipher: aes192-cbc MAC: hmac-sha1 compression: none debug1: sending SSH2_MSG_KEXDH_INIT debug2: bits set: 1015/2048 debug3: send packet: type 30 debug1: expecting SSH2_MSG_KEXDH_REPLY debug3: receive packet: type 31 debug1: Server host key: ssh-rsa SHA256:0oLfkrEjIEDItjZDXCt+5EJuVSLzjNuO0apIZtrFnXA debug3: put_host_port: [1.2.3.4]:32 debug3: put_host_port: [IBM.SFG.SFTP.server]:32 debug3: hostkeys_foreach: reading file "/root/.ssh/known_hosts" debug3: record_hostkey: found key type RSA in file /root/.ssh/known_hosts:57 debug3: load_hostkeys: loaded 1 keys from [IBM.SFG.SFTP.server]:32 debug3: hostkeys_foreach: reading file "/root/.ssh/known_hosts" debug3: record_hostkey: found key type RSA in file /root/.ssh/known_hosts:57 debug3: load_hostkeys: loaded 1 keys from [1.2.3.4]:32 debug1: Host '[IBM.SFG.SFTP.server]:32' is known and matches the RSA host key. debug1: Found key in /root/.ssh/known_hosts:57 debug2: bits set: 1022/2048 debug3: send packet: type 21 debug2: set_newkeys: mode 1 debug1: rekey after 4294967296 blocks debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug3: receive packet: type 21 debug2: set_newkeys: mode 0 debug1: rekey after 4294967296 blocks debug1: SSH2_MSG_NEWKEYS received debug2: key: /root/.ssh/id_rsa (0x5590b459ff30) debug2: key: /root/.ssh/id_dsa ((nil)) debug2: key: /root/.ssh/id_ecdsa ((nil)) debug2: key: /root/.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 53 debug3: input_userauth_banner Thank You debug3: receive packet: type 51 debug1: Authentications that can continue: keyboard-interactive,publickey,password debug3: start over, passed a different list keyboard-interactive,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: Offering RSA public key: /root/.ssh/id_rsa debug3: send_pubkey_test debug3: send packet: type 50 debug2: we sent a publickey packet, wait for reply debug3: receive packet: type 51 debug1: Authentications that can continue: keyboard-interactive,publickey,password debug1: Trying private key: /root/.ssh/id_dsa debug3: no such identity: /root/.ssh/id_dsa: No such file or directory debug1: Trying private key: /root/.ssh/id_ecdsa debug3: no such identity: /root/.ssh/id_ecdsa: No such file or directory debug1: Trying private key: /root/.ssh/id_ed25519 debug3: no such identity: /root/.ssh/id_ed25519: No such file or directory debug2: we did not send a packet, disable method debug3: authmethod_lookup keyboard-interactive debug3: remaining preferred: password debug3: authmethod_is_enabled keyboard-interactive debug1: Next authentication method: keyboard-interactive debug2: userauth_kbdint debug3: send packet: type 50 debug2: we sent a keyboard-interactive packet, wait for reply debug3: receive packet: type 51 debug1: Authentications that can continue: keyboard-interactive,publickey,password debug3: userauth_kbdint: disable: no info_req_seen debug2: we did not send a packet, disable method debug3: authmethod_lookup password debug3: remaining preferred: debug3: authmethod_is_enabled password debug1: Next authentication method: password SOMEUSER@xxxxxxxxxxxx.server's password: debug3: send packet: type 50 debug2: we sent a password packet, wait for reply debug3: receive packet: type 2 debug3: Received SSH2_MSG_IGNORE debug3: receive packet: type 51 debug1: Authentications that can continue: keyboard-interactive,publickey,password Permission denied, please try again. SOMEUSER@xxxxxxxxxxxx.server's password: debug3: send packet: type 50 debug2: we sent a password packet, wait for reply debug3: receive packet: type 51 debug1: Authentications that can continue: keyboard-interactive,publickey,password Permission denied, please try again. SOMEUSER@xxxxxxxxxxxx.server's password: debug3: send packet: type 50 debug2: we sent a password packet, wait for reply debug3: receive packet: type 1 Received disconnect from 1.2.3.4 port 32:11: Too many bad authentication attempts! debug1: Authentication succeeded (password). Authenticated to IBM.SFG.SFTP.server ([1.2.3.4]:32). debug2: fd 4 setting O_NONBLOCK debug3: fd 5 is O_NONBLOCK debug1: channel 0: new [client-session] debug3: ssh_session2_open: channel_new: 0 debug2: channel 0: send open debug3: send packet: type 90 debug1: Entering interactive session. debug1: pledge: network debug3: send packet: type 1 debug1: channel 0: free: client-session, nchannels 1 debug3: channel 0: status: The following connections are open: #0 client-session (t3 r-1 i0/0 o0/0 fd 4/5 cc -1) debug1: fd 0 clearing O_NONBLOCK debug3: fd 1 is not O_NONBLOCK Connection to IBM.SFG.SFTP.server closed by remote host. Transferred: sent 2480, received 1744 bytes, in 0.0 seconds Bytes per second: sent 6393284.5, received 4495922.7 debug1: Exit status -1 Couldn't read packet: Connection reset by peer -----Original Message----- From: Damien Miller [mailto:djm@xxxxxxxxxxx] Sent: Wednesday, September 21, 2016 11:03 AM To: Delisle, John <john.delisle@xxxxxxxxxxxx> Cc: openssh-unix-dev@xxxxxxxxxxx; Babcock, Peter <Peter.Babcock@xxxxxxxxxxxx>; Olbruck, Eric <Eric.Olbruck@xxxxxxxxxxxx> Subject: Re: Where to look next? On Wed, 21 Sep 2016, Delisle, John wrote: > Hello, > > I'm looking for your insight about the log below. We have an SFTP > server (IBM Sterling File Gateway) and we're connecting from an > OpenSSH SFTP client but something fails during KEX. > > Complete client-side debug output is below, but I believe the relevant > part is: > > debug1: kex: server->client cipher: aes192-cbc MAC: hmac-sha1 > compression: none > debug1: kex: client->server cipher: aes192-cbc MAC: hmac-sha1 > compression: none > debug3: send packet: type 30 > debug1: sending SSH2_MSG_KEX_ECDH_INIT > debug1: expecting SSH2_MSG_KEX_ECDH_REPLY > debug3: receive packet: type 1 > Received disconnect from 1.2.3.4 port 32:2: Failed to read binary packet data! > > Any suggestions about what's failing, and what the cause might be? > We're trying to figure out where to go in our troubleshooting, and do > not understand the meaning of this debug output. It's failing during key exchange (KEX). You could try explicitly selecting a different key exchange method e.g. sftp -oKEXAlgorithms=diffie-hellman-group14-sha1 ... If that works then it's highly likely that the IBM server has implemented the ecdh-sha2-nistp256 method incorrectly. -d _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
