The server was fine in the morning. But when I came back from lunch, I suddenly found that the server could not board. By the way, my laptop is Macbook air.
The error reported by entering ssh lab in the terminal was:
> user@.. ~ % ssh lab
kex_exchange_identification: Connection closed by remote host
Connection closed by xxx.xx.x.xxx port 22
Entering ssh -v [email protected] again reports the error in more detail as follows:
> user@... ~ % ssh -v [email protected]
OpenSSH_9.0p1, LibreSSL 3.3.6
debug1: Reading configuration data /Users/.../.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 21: include /etc/ssh/ssh_config.d/* matched no files
debug1: /etc/ssh/ssh_config line 54: Applying options for *
debug1: Authenticator provider $SSH_SK_PROVIDER did not resolve; disabling
debug1: Connecting to xxx.xxx.xxx.xxx [xxx.xxx.xxx.xxx] port 22.
debug1: Connection established.
debug1: identity file /Users/.../.ssh/id_rsa type 0
debug1: identity file /Users/.../.ssh/id_rsa-cert type -1
debug1: identity file /Users/.../.ssh/id_ecdsa type -1
debug1: identity file /Users/.../.ssh/id_ecdsa-cert type -1
debug1: identity file /Users/.../.ssh/id_ecdsa_sk type -1
debug1: identity file /Users/.../.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /Users/.../.ssh/id_ed25519 type -1
debug1: identity file /Users/..../ssh/id_ed25519-cert type -1
debug1: identity file /Users/.../.ssh/id_ed25519_sk type -1
debug1: identity file /Users/.../.ssh/id_ed25519_sk-cert type -1
debug1: identity file /Users/.../.ssh/id_xmss type -1
debug1: identity file /Users/.../.ssh/id_xmss-cert type -1
debug1: identity file /Users/.../.ssh/id_dsa type -1
debug1: identity file /Users/.../.ssh/id_dsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_9.0
debug1: Remote protocol version 2.0, remote software version OpenSSH_8.0
debug1: compat_banner: match: OpenSSH_8.0 pat OpenSSH* compat 0x04000000
debug1: Authenticating to xxx.xxx.xxx.xx:22 as 'lab'
debug1: load_hostkeys: fopen /Users/.../.ssh/known_hosts2: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts2: No such file or directory
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ssh-ed25519
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: SSH2_MSG_KEX_ECDH_REPLY received
debug1: Server host key: ...
debug1: load_hostkeys: fopen /Users/.../.ssh/known_hosts2: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts: No such file or directory
debug1: load_hostkeys: fopen /etc/ssh/ssh_known_hosts2: No such file or directory
debug1: Host 'xxx.xxx.xxx.xxx' is known and matches the ED25519 host key.
debug1: Found key in /Users/zkey/.ssh/known_hosts:1
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey in after 134217728 blocks
debug1: get_agent_identities: bound agent to hostkey
debug1: get_agent_identities: ssh_fetch_identitylist: agent contains no identities
debug1: Will attempt key: /Users/.../.ssh/id_rsa ...
debug1: Will attempt key: /Users/.../.ssh/id_ecdsa
debug1: Will attempt key: /Users/.../.ssh/id_ecdsa_sk
debug1: Will attempt key: /Users/.../.ssh/id_ed25519
debug1: Will attempt key: /Users/.../.ssh/id_ed25519_sk
debug1: Will attempt key: /Users/.../.ssh/id_xmss
debug1: Will attempt key: /Users/.../.ssh/id_dsa
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: ...
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic
debug1: Next authentication method: publickey
debug1: Offering public key: /Users/.../.ssh/id_rsa RSA ...
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic
debug1: Trying private key: /Users/.../.ssh/id_ecdsa
debug1: Trying private key: /Users/.../.ssh/id_ecdsa_sk
debug1: Trying private key: /Users/.../.ssh/id_ed25519
debug1: Trying private key: /Users/.../.ssh/id_ed25519_sk
debug1: Trying private key: /Users/.../.ssh/id_xmss
debug1: Trying private key: /Users/.../.ssh/id_dsa
debug1: No more authentication methods to try.
[email protected]: Permission denied (publickey,gssapi-keyex,gssapi-with-mic).
Ask how this can be fixed! Thanks! Otherwise I wouldn't have gotten my work done. Orz
I also tried to connect to the server remotely in VScode, but it reports an error Could not establish connection to "lab".
The problem has already been solved.
I found that there were two strange lines in the ~/.ssh.config file,
they are:
Host xxx HostName xxx.xx.xxx.xxx
I don't know where they came from. But after I delete them, I can connect to the server.