客户端是带有keychain Ubuntu 16.04，服务器是FreeBSD 10.3。 在服务器上的~/.ssh/authorized_keys只有一个密钥（这个密钥是ECDSA p521而不是RSA），客户端在~/.ssh有私钥和~/.ssh 。 问题是，客户端不断发送所有RSA密钥在其~/.ssh首先可以看到这个详细的输出：
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).
即使我在客户端的~/.ssh/config指定了这个输出，仍然是相同的输出：
host r2d2.manuth.life IdentityFile ~/.ssh/dqar Port 900
试图从keychain删除所有的钥匙，但没有帮助。 如果我将RSA公钥添加到服务器上，那么在客户端的~/.ssh/config指定RSA私钥，它会立即拿起RSA密钥。
从这里find答案： https ： //linux-audit.com/using-ed25519-openssh-keys-instead-of-dsa-rsa-ecdsa/
基本上我必须添加到客户端的~/.ssh/config ：
IdentitiesOnly yes