客户端是 Ubuntu 16.04 keychain，服务器是 FreeBSD 10.3。服务器上只有一个密钥~/.ssh/authorized_keys（这个密钥是 ECDSA p521 而不是 RSA），并且客户端里面有私钥和公钥~/.ssh。问题是客户端不断发送所有可用的 RSA 密钥~/.ssh- 请参阅此详细输出：
OpenSSH_7.2p2 Ubuntu-4, OpenSSL 1.0.2g-fips 1 Mar 2016
debug1: Reading configuration data /home/manuth/.ssh/config
debug1: /home/manuth/.ssh/config line 1: Applying options for r2d2.manuth.life
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to r2d2.manuth.life [103.12.163.90] port 900.
debug1: Connection established.
debug1: identity file /home/manuth/.ssh/dqar type 3
debug1: key_load_public: No such file or directory
debug1: identity file /home/manuth/.ssh/dqar-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2 FreeBSD-20160310
debug1: match: OpenSSH_7.2 FreeBSD-20160310 pat OpenSSH* compat 0x04000000
debug1: Authenticating to r2d2.manuth.life:900 as 'manuth'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: [email protected]
debug1: kex: host key algorithm: ecdsa-sha2-nistp521
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: Server host key: ecdsa-sha2-nistp521 SHA256:awtuO9udROeroYOv3GJ8Z6xcHt4IQhjNkcKQ6eavuik
debug1: Host '[r2d2.manuth.life]:900' is known and matches the ECDSA host key.
debug1: Found key in /home/manuth/.ssh/known_hosts:10
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering RSA public key: manuth@wackypc
debug1: Authentications that can continue: publickey
debug1: Offering RSA public key: manuth@wackypc
debug1: Authentications that can continue: publickey
debug1: Offering RSA public key: manuth@wackypc
debug1: Authentications that can continue: publickey
debug1: Offering ECDSA public key: /home/manuth/.ssh/dqar
debug1: Server accepts key: pkalg ecdsa-sha2-nistp521 blen 172
debug1: Authentication succeeded (publickey).
Authenticated to r2d2.manuth.life ([103.12.163.90]:900).
即使我~/.ssh/config在客户端上指定它，输出仍然相同：
host r2d2.manuth.life
IdentityFile ~/.ssh/dqar
Port 900
尝试从中删除所有键，keychain但没有帮助。如果我将 RSA 公钥添加到服务器，然后在~/.ssh/config客户端上指定 RSA 私钥，它会立即获取 RSA 密钥。
从这里找到答案： https ://linux-audit.com/using-ed25519-openssh-keys-instead-of-dsa-rsa-ecdsa/
基本上我必须将此添加到客户的
~/.ssh/config：IdentitiesOnly yes