O problema é causado pela configuração incorreta do DNS. O cliente ssh usa o IPv6 e o 'myserver.lan' está sendo resolvido para [:: 1]. Você precisa remover o registro AAAA :: 1 do seu arquivo de configuração da zona e reiniciar o nome.
Eu apenas reiniciei meu servidor Ubuntu 16.04 e comecei a receber o erro "AVISO: A IDENTIFICAÇÃO DO HOST REMOTO FOI MUDADA!" ao tentar usar ssh no nome DNS ssh [email protected] . Inicialmente, apenas removi as entradas de known_hosts e tentei novamente, mas percebi que na verdade não estava aceitando minha senha.
Fazer ssh [email protected] usando o endereço IP ainda funciona e até meu login sem senha ainda funciona.
Esta é a saída de nslookup myserver.lan , que mostra que o DNS está retornando o endereço correto:
Server: 192.168.1.2
Address: 192.168.1.2#53
Name: myserver.lan
Address: 192.168.1.2
Esta é a saída detalhada de 'ssh [email protected]', que é bem sucedida:
OpenSSH_6.9p1, LibreSSL 2.1.8
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: /etc/ssh/ssh_config line 56: Applying options for *
debug1: Connecting to 192.168.1.2 [192.168.1.2] port 22.
debug1: Connection established.
debug1: identity file /Users/jimbo/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.1
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.1 pat OpenSSH* compat 0x04000000
debug1: Authenticating to 192.168.1.2:22 as 'me'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client [email protected] <implicit> none
debug1: kex: client->server [email protected] <implicit> none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:ZOO3YXwox2kHpLokBRXzPvuUFPOrposhAgnpQCaZ5+I
The authenticity of host '192.168.1.2 (192.168.1.2)' can't be established.
ECDSA key fingerprint is SHA256:ZOO3YXwox2kHpLokBRXzPvuUFPOrposhAgnpQCaZ5+I.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.2' (ECDSA) to the list of known hosts.
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/jimbo/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 279
debug1: Authentication succeeded (publickey).
Authenticated to 192.168.1.2 ([192.168.1.2]:22).
debug1: channel 0: new [client-session]
debug1: Requesting [email protected]
debug1: Entering interactive session.
debug1: client_input_global_request: rtype [email protected] want_reply 0
debug1: Sending environment.
debug1: Sending env LANG = en_GB.UTF-8
Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.4.0-78-generic x86_64)
E esta é a saída detalhada de ssh [email protected] , que falha e não reconhece minha senha:
OpenSSH_6.9p1, LibreSSL 2.1.8
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: /etc/ssh/ssh_config line 56: Applying options for *
debug1: Connecting to myserver.lan [::1] port 22.
debug1: Connection established.
debug1: identity file /Users/jimbo/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/jimbo/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_6.9
debug1: match: OpenSSH_6.9 pat OpenSSH* compat 0x04000000
debug1: Authenticating to myserver.lan:22 as 'me'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client [email protected] <implicit> none
debug1: kex: client->server [email protected] <implicit> none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:WDp/1JiHcWk6Lpcgfrl+/pDbSmdFxVTZFDfVhTEqBCg
debug1: Host 'myserver.lan' is known and matches the ECDSA host key.
debug1: Found key in /Users/jimbo/.ssh/known_hosts:5
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /Users/jimbo/.ssh/id_rsa
debug1: Authentications that can continue: publickey,keyboard-interactive
debug1: Trying private key: /Users/jimbo/.ssh/id_dsa
debug1: Trying private key: /Users/jimbo/.ssh/id_ecdsa
debug1: Trying private key: /Users/jimbo/.ssh/id_ed25519
debug1: Next authentication method: keyboard-interactive
Password:
Como você pode ver, as chaves de host retornadas são diferentes. Isso é correto para esperar chaves diferentes ao usar o nome do host vs o endereço IP. Quais são os próximos passos que posso dar?
Parece que o ssh está resolvendo o nome do host para localhost, já que eu obtenho a mesma chave do host ao sshing para localhost.
Meu arquivo de hosts é basicamente vazio:
127.0.0.1 localhost
255.255.255.255 broadcasthost
::1 localhost
Mas host myserver.lan retorna isso. Isso tem algo a ver com a configuração do IPv6?
host myserver.lan
myserver.lan has address 192.168.1.2
myserver.lan has IPv6 address ::1
Esta é a saída de dig @192.168.1.2 myserver.lan
; <<>> DiG 9.8.3-P1 <<>> @192.168.1.2 myserver.lan
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32577
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1
;; QUESTION SECTION:
;myserver.lan. IN A
;; ANSWER SECTION:
myserver.lan. 604800 IN A 192.168.1.2
;; AUTHORITY SECTION:
myserver.lan. 604800 IN NS ns.myserver.lan.
;; ADDITIONAL SECTION:
ns.myserver.lan. 604800 IN A 192.168.1.2
;; Query time: 21 msec
;; SERVER: 192.168.1.2#53(192.168.1.2)
;; WHEN: Sun May 21 13:34:41 2017
;; MSG SIZE rcvd: 79
E o arquivo de configuração de ligação no servidor:
;
; BIND data file for myserver
$TTL 604800
@ IN SOA myserver.lan. root.myserver.lan. (
3 ; Serial
604800 ; Refresh
86400 ; Retry
2419200 ; Expire
604800 ) ; Negative Cache TTL
IN A 192.168.1.2
;
@ IN NS ns.myserver.lan.
@ IN A 192.168.1.2
@ IN AAAA ::1
ns IN A 192.168.1.2
P.S. Eu tenho um laptop com windows cygwin que ainda é capaz de logar no servidor usando o nome do host. Apenas meu Mac parece estar afetado.