Thanks for the reply, the client is using 7.2 and the server is on 6.6 version. And, here are the debug files attached. Thanks, Mahoda With Change: ========================================================================================= OpenSSH_7.2p2, OpenSSL 1.0.2h 3 May 2016 debug1: Reading configuration data /etc/ssh/ssh_config debug2: resolving "192.168.1.1" port 22 debug2: ssh_connect_direct: needpriv 0 debug1: Connecting to 192.168.1.1 [192.168.1.1] port 22. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/identity type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/identity-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_rsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_rsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_dsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_dsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_ecdsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_ecdsa-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-AtiSSH_2.0 debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.8 debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.8 pat OpenSSH_6.6.1* compat 0x04000000 debug2: fd 3 setting O_NONBLOCK 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@xxxxxxxxxx ,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@xxxxxxxxxxx, ecdsa-sha2-nistp384-cert-v01@xxxxxxxxxxx, ecdsa-sha2-nistp521-cert-v01@xxxxxxxxxxx,ssh-ed25519-cert-v01@xxxxxxxxxxx, ssh-rsa-cert-v01@xxxxxxxxxxx ,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-dss 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: curve25519-sha256@xxxxxxxxxx ,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: host key algorithms: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ssh-ed25519 debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128, aes128-gcm@xxxxxxxxxxx,aes256-gcm@xxxxxxxxxxx,chacha20-poly1305@xxxxxxxxxxx ,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour, rijndael-cbc@xxxxxxxxxxxxxx debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128, aes128-gcm@xxxxxxxxxxx,aes256-gcm@xxxxxxxxxxx,chacha20-poly1305@xxxxxxxxxxx ,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour, rijndael-cbc@xxxxxxxxxxxxxx debug2: MACs ctos: hmac-md5-etm@xxxxxxxxxxx,hmac-sha1-etm@xxxxxxxxxxx, umac-64-etm@xxxxxxxxxxx,umac-128-etm@xxxxxxxxxxx, hmac-sha2-256-etm@xxxxxxxxxxx,hmac-sha2-512-etm@xxxxxxxxxxx, hmac-ripemd160-etm@xxxxxxxxxxx,hmac-sha1-96-etm@xxxxxxxxxxx, hmac-md5-96-etm@xxxxxxxxxxx,hmac-md5,hmac-sha1,umac-64@xxxxxxxxxxx, umac-128@xxxxxxxxxxx,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160, hmac-ripemd160@xxxxxxxxxxx,hmac-sha1-96,hmac-md5-96 debug2: MACs stoc: hmac-md5-etm@xxxxxxxxxxx,hmac-sha1-etm@xxxxxxxxxxx, umac-64-etm@xxxxxxxxxxx,umac-128-etm@xxxxxxxxxxx, hmac-sha2-256-etm@xxxxxxxxxxx,hmac-sha2-512-etm@xxxxxxxxxxx, hmac-ripemd160-etm@xxxxxxxxxxx,hmac-sha1-96-etm@xxxxxxxxxxx, hmac-md5-96-etm@xxxxxxxxxxx,hmac-md5,hmac-sha1,umac-64@xxxxxxxxxxx, umac-128@xxxxxxxxxxx,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160, hmac-ripemd160@xxxxxxxxxxx,hmac-sha1-96,hmac-md5-96 debug2: compression ctos: none,zlib@xxxxxxxxxxx debug2: compression stoc: none,zlib@xxxxxxxxxxx debug2: languages ctos: debug2: languages stoc: debug2: first_kex_follows 0 debug2: reserved 0 debug1: kex: algorithm: curve25519-sha256@xxxxxxxxxx debug1: kex: host key algorithm: ecdsa-sha2-nistp256 debug1: kex: server->client cipher: chacha20-poly1305@xxxxxxxxxxx MAC: <implicit> compression: none debug1: kex: client->server cipher: chacha20-poly1305@xxxxxxxxxxx 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:IwZ3AJCkBnQypTalkkezSSXShPg/+1eEDgHS65R8dN0 debug3: hostkeys_foreach: reading file "/flash/.home/root/.ssh/known_hosts" debug3: hostkeys_foreach: reading file "/flash/.configs/ssh/ssh_known_hosts" debug3: record_hostkey: found key type RSA in file /flash/.configs/ssh/ssh_known_hosts:2 debug3: load_hostkeys: loaded 1 keys from 192.168.1.1 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that a host key has just been changed. The fingerprint for the ECDSA key sent by the remote host is SHA256:IwZ3AJCkBnQypTalkkezSSXShPg/+1eEDgHS65R8dN0. Please contact your system administrator. ECDSA host key for 192.168.1.1 has changed and you have requested strict checking. Host key verification failed. ============================================================================================================================================= Without change: ============================================================================================================================================= OpenSSH_7.2p2, OpenSSL 1.0.2h 3 May 2016 debug1: Reading configuration data /etc/ssh/ssh_config debug2: resolving "192.168.1.1" port 22 debug2: ssh_connect_direct: needpriv 0 debug1: Connecting to 192.168.1.1 [192.168.1.1] port 22. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/identity type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/identity-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_rsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_rsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_dsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_dsa-cert type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_ecdsa type -1 debug1: key_load_public: No such file or directory debug1: identity file /flash/.home/root/.ssh/id_ecdsa-cert type -1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-AtiSSH_2.0 debug1: Remote protocol version 2.0, remote software version OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.8 debug1: match: OpenSSH_6.6.1p1 Ubuntu-2ubuntu2.8 pat OpenSSH_6.6.1* compat 0x04000000 debug2: fd 3 setting O_NONBLOCK debug3: hostkeys_foreach: reading file "/flash/.home/root/.ssh/known_hosts" debug3: hostkeys_foreach: reading file "/flash/.configs/ssh/ssh_known_hosts" debug3: record_hostkey: found key type RSA in file /flash/.configs/ssh/ssh_known_hosts:2 debug3: load_hostkeys: loaded 1 keys from 192.168.1.1 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: curve25519-sha256@xxxxxxxxxx ,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: 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: curve25519-sha256@xxxxxxxxxx ,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: host key algorithms: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ssh-ed25519 debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128, aes128-gcm@xxxxxxxxxxx,aes256-gcm@xxxxxxxxxxx,chacha20-poly1305@xxxxxxxxxxx ,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour, rijndael-cbc@xxxxxxxxxxxxxx debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128, aes128-gcm@xxxxxxxxxxx,aes256-gcm@xxxxxxxxxxx,chacha20-poly1305@xxxxxxxxxxx ,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour, rijndael-cbc@xxxxxxxxxxxxxx debug2: MACs ctos: hmac-md5-etm@xxxxxxxxxxx,hmac-sha1-etm@xxxxxxxxxxx, umac-64-etm@xxxxxxxxxxx,umac-128-etm@xxxxxxxxxxx, hmac-sha2-256-etm@xxxxxxxxxxx,hmac-sha2-512-etm@xxxxxxxxxxx, hmac-ripemd160-etm@xxxxxxxxxxx,hmac-sha1-96-etm@xxxxxxxxxxx, hmac-md5-96-etm@xxxxxxxxxxx,hmac-md5,hmac-sha1,umac-64@xxxxxxxxxxx, umac-128@xxxxxxxxxxx,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160, hmac-ripemd160@xxxxxxxxxxx,hmac-sha1-96,hmac-md5-96 debug2: MACs stoc: hmac-md5-etm@xxxxxxxxxxx,hmac-sha1-etm@xxxxxxxxxxx, umac-64-etm@xxxxxxxxxxx,umac-128-etm@xxxxxxxxxxx, hmac-sha2-256-etm@xxxxxxxxxxx,hmac-sha2-512-etm@xxxxxxxxxxx, hmac-ripemd160-etm@xxxxxxxxxxx,hmac-sha1-96-etm@xxxxxxxxxxx, hmac-md5-96-etm@xxxxxxxxxxx,hmac-md5,hmac-sha1,umac-64@xxxxxxxxxxx, umac-128@xxxxxxxxxxx,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160, hmac-ripemd160@xxxxxxxxxxx,hmac-sha1-96,hmac-md5-96 debug2: compression ctos: none,zlib@xxxxxxxxxxx debug2: compression stoc: none,zlib@xxxxxxxxxxx debug2: languages ctos: debug2: languages stoc: debug2: first_kex_follows 0 debug2: reserved 0 debug1: kex: algorithm: curve25519-sha256@xxxxxxxxxx debug1: kex: host key algorithm: ssh-rsa debug1: kex: server->client cipher: chacha20-poly1305@xxxxxxxxxxx MAC: <implicit> compression: none debug1: kex: client->server cipher: chacha20-poly1305@xxxxxxxxxxx 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: ssh-rsa SHA256:UWb75G/DzMWOCH4KNR4As0lYcpI1POgD7TEX9iXYSLA debug3: hostkeys_foreach: reading file "/flash/.home/root/.ssh/known_hosts" debug3: hostkeys_foreach: reading file "/flash/.configs/ssh/ssh_known_hosts" debug3: record_hostkey: found key type RSA in file /flash/.configs/ssh/ssh_known_hosts:2 debug3: load_hostkeys: loaded 1 keys from 192.168.1.1 debug1: Host '192.168.1.1' is known and matches the RSA host key. debug1: Found key in /flash/.configs/ssh/ssh_known_hosts:2 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 debug2: key: /flash/.home/root/.ssh/identity ((nil)) debug2: key: /flash/.home/root/.ssh/id_rsa ((nil)) debug2: key: /flash/.home/root/.ssh/id_dsa ((nil)) debug2: key: /flash/.home/root/.ssh/id_ecdsa ((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: /flash/.home/root/.ssh/identity debug3: no such identity: /flash/.home/root/.ssh/identity: No such file or directory debug1: Trying private key: /flash/.home/root/.ssh/id_rsa debug3: no such identity: /flash/.home/root/.ssh/id_rsa: No such file or directory debug1: Trying private key: /flash/.home/root/.ssh/id_dsa debug3: no such identity: /flash/.home/root/.ssh/id_dsa: No such file or directory debug1: Trying private key: /flash/.home/root/.ssh/id_ecdsa debug3: no such identity: /flash/.home/root/.ssh/id_ecdsa: 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 =========================================================================================================================================== On 7 September 2016 at 16:53, Darren Tucker <dtucker@xxxxxxxxxx> wrote: > On Wed, Sep 7, 2016 at 1:59 PM, Mahoda Ratnayaka <mahodardev@xxxxxxxxx> > wrote: > > I'm having a problem when I add "HostKeyAlgorithms +ssh-dss" to the > > ssh_config file the host key will always negotiate to a wrong one. In my > > case it will negotiate to "ecdsa-sha2-nistp256". The client was already > > configured with the servers rsa public key, before the change I added to > > the ssh_config file I could see from the debug that server and client > will > > negotiate to use ssh-rsa as expected. After change unfortunately the > client > > and server will negotiate to use ecdsa-sha2-nistp256, then later will > > complain "REMOTE HOST IDENTIFICATION HAS CHANGED" and fail. I got around > > this by adding the ecdsa public key to the know hosts. > > What version of OpenSSH is this? Can you post debug output (ssh -vvv) > with and without the +ssh-dss option? > > -- > 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. > _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
