我在为 LAN 上的笔记本电脑设置 ssh 时遇到了困难。我想我已经做了所有显而易见的事情。在服务器上：
ps -A | grep sshd
18278 ? 00:00:00 sshd
和
ss -lnp
显示 sshd 正在监听端口 22。我检查了 hosts.deny 和 hosts.allow，都是空的。UFW 显示端口 22 上允许的连接，并且路由器防火墙已关闭。
在客户端上：
ssh -v [email protected] martin@martin-UX21E 7:54PM
OpenSSH_5.9p1 Debian-5ubuntu1, OpenSSL 1.0.1 14 Mar 2012
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to 192.168.2.12 [192.168.2.12] port 22.
debug1: Connection established.
debug1: identity file /home/martin/.ssh/id_rsa type -1
debug1: identity file /home/martin/.ssh/id_rsa-cert type -1
debug1: identity file /home/martin/.ssh/id_dsa type -1
debug1: identity file /home/martin/.ssh/id_dsa-cert type -1
debug1: identity file /home/martin/.ssh/id_ecdsa type -1
debug1: identity file /home/martin/.ssh/id_ecdsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.9p1 Debian-5ubuntu1
debug1: match: OpenSSH_5.9p1 Debian-5ubuntu1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9p1 Debian-5ubuntu1
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: sending SSH2_MSG_KEX_ECDH_INIT
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ECDSA 36:bf:c0:c6:d1:e0:16:bd:f0:8c:88:fe:1b:4b:12:74
debug1: Host '192.168.2.12' is known and matches the ECDSA host key.
debug1: Found key in /home/martin/.ssh/known_hosts:1
debug1: ssh_ecdsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
Connection closed by 192.168.2.12
在服务器上，
ssh localhost
工作正常，但是
ssh 192.168.2.12
不会。出于某种原因，它乐意接受使用主机名的连接，但不愿意接受使用 IP 地址的连接。
有人可以建议下一步的故障排除步骤吗？
回复 victorcete83：
ssh -vvv [email protected] martin@martin-UX21E 8:00PM
OpenSSH_5.9p1 Debian-5ubuntu1, OpenSSL 1.0.1 14 Mar 2012
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.2.12 [192.168.2.12] port 22.
debug1: Connection established.
debug1: identity file /home/martin/.ssh/id_rsa type -1
debug1: identity file /home/martin/.ssh/id_rsa-cert type -1
debug1: identity file /home/martin/.ssh/id_dsa type -1
debug1: identity file /home/martin/.ssh/id_dsa-cert type -1
debug1: identity file /home/martin/.ssh/id_ecdsa type -1
debug1: identity file /home/martin/.ssh/id_ecdsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.9p1 Debian-5ubuntu1
debug1: match: OpenSSH_5.9p1 Debian-5ubuntu1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.9p1 Debian-5ubuntu1
debug2: fd 3 setting O_NONBLOCK
debug3: load_hostkeys: loading entries for host "192.168.2.12" from file "/home/martin/.ssh/known_hosts"
debug3: load_hostkeys: found key type ECDSA in file /home/martin/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],[email protected],[email protected],ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,[email protected],zlib
debug2: kex_parse_kexinit: none,[email protected],zlib
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,[email protected]
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,[email protected],hmac-sha2-256,hmac-sha2-256-96,hmac-sha2-512,hmac-sha2-512-96,hmac-ripemd160,[email protected],hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,[email protected]
debug2: kex_parse_kexinit: none,[email protected]
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit:
debug2: kex_parse_kexinit: first_kex_follows 0
debug2: kex_parse_kexinit: reserved 0
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-ctr hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: sending SSH2_MSG_KEX_ECDH_INIT
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ECDSA 36:bf:c0:c6:d1:e0:16:bd:f0:8c:88:fe:1b:4b:12:74
debug3: load_hostkeys: loading entries for host "192.168.2.12" from file "/home/martin/.ssh/known_hosts"
debug3: load_hostkeys: found key type ECDSA in file /home/martin/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys
debug1: Host '192.168.2.12' is known and matches the ECDSA host key.
debug1: Found key in /home/martin/.ssh/known_hosts:1
debug1: ssh_ecdsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /home/martin/.ssh/id_rsa ((nil))
debug2: key: /home/martin/.ssh/id_dsa ((nil))
debug2: key: /home/martin/.ssh/id_ecdsa ((nil))
Connection closed by 192.168.2.12
答案1
如果 ssh 连接作品指向 localhost，意味着它将访问 127.0.0.1。如果它失败指向 192.168.2.12 应该是因为您的 ssh 正在监听 127.0.0.1 (localhost)。
检查你的ListenAddresssshd 配置文件。
答案2
另一个想法是在服务器上手动运行 sshd 守护进程，并使用标志-d在服务器上生成更多的调试输出。它将停留在前台并在控制台上输出首次信息。
-p <portnumber>您可以使用启动第二个守护进程时的选项在另一个端口上并行运行第二个 sshd 守护进程。
答案3
尝试从另一台局域网主机 ssh 到您的笔记本电脑。我猜是您的 .ssh 目录中有一些损坏或不匹配的密钥。从另一台主机启动可以消除 .ssh 目录中除 authorized_keys 之外的内容是问题所在。
答案4
从你的终端尝试以下命令：
sudo ufw app list
如果你看到下面这句话：
Available applications:
...
OpenSSH
...
那么你应该运行
sudo ufw allow 'OpenSSH'
这对我有用。