当我尝试使用命令连接到远程主机时ssh -vv hostname，它会挂起一段时间，然后关闭连接。
如果我指定以下命令，我就可以连接：
ssh -c aes128-ctr hostname
问题是为什么我必须指定具体的密码？
第一种情况下的调试输出底部如下所示：
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: aes128-ctr,aes192-ctr,aes256-ctr
debug2: ciphers stoc: aes128-ctr,aes192-ctr,aes256-ctr
debug2: MACs ctos: hmac-sha1,hmac-ripemd160
debug2: MACs stoc: hmac-sha1,hmac-ripemd160
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: aes128-ctr MAC: hmac-sha1 compression: none
debug1: kex: client->server cipher: aes128-ctr MAC: hmac-sha1 compression: none
debug1: kex: curve25519-sha256 need=20 dh_need=20
debug1: kex: curve25519-sha256 need=20 dh_need=20
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY