问题[sshd](ubuntu)

我正在尝试从运行 ubuntu 22.04 的客户端使用 SSH 连接到远程服务器

服务器是 OVH ISP 的云实例，运行 ubuntu 23.04。

OVH 文档中提到：“您只能存储 RSA 和 ECDSA 加密密钥；目前不支持 ED25519。”。所以我按照他们的建议在我的客户端上创建了一个 RSA 密钥，使用：

ssh-keygen -b 4096，并将密钥复制到云实例服务器。

现在，当我尝试连接时，使用：

ssh [email protected]

我得到：

The authenticity of host '135.125.94.203' can't be established. ED25519 key fingerprint is SHA256:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx. This key is not known by any other names Are you sure you want to continue connecting (yes/no/[fingerprint])?

当我回答是时，我得到：[email protected]: Permission denied (publickey).

我阅读了不同的消息，但首先我不明白为什么提到 ED25519，因为我创建了一个 RSA 密钥。

PubkeyAcceptedKeyTypes +ssh-rsa我试图在 /etc/ssh/sshd_config 的末尾添加：并重新启动 ssh，但它没有帮助。

下面是日志ssh -vvv [email protected]

OpenSSH_8.9p1 Ubuntu-3ubuntu0.1, OpenSSL 3.0.2 15 Mar 2022
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: resolve_canonicalize: hostname 135.125.94.203 is address
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' -> '/home/mp/.ssh/known_hosts'
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' -> '/home/mp/.ssh/known_hosts2'
debug3: ssh_connect_direct: entering
debug1: Connecting to 135.125.94.203 [135.125.94.203] port 22.
debug3: set_sock_tos: set socket 3 IP_TOS 0x10
debug1: Connection established.
debug1: identity file /home/mp/.ssh/id_rsa type 0
debug1: identity file /home/mp/.ssh/id_rsa-cert type -1
debug1: identity file /home/mp/.ssh/id_ecdsa type -1
debug1: identity file /home/mp/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/mp/.ssh/id_ecdsa_sk type -1
debug1: identity file /home/mp/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /home/mp/.ssh/id_ed25519 type -1
debug1: identity file /home/mp/.ssh/id_ed25519-cert type -1
debug1: identity file /home/mp/.ssh/id_ed25519_sk type -1
debug1: identity file /home/mp/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /home/mp/.ssh/id_xmss type -1
debug1: identity file /home/mp/.ssh/id_xmss-cert type -1
debug1: identity file /home/mp/.ssh/id_dsa type -1
debug1: identity file /home/mp/.ssh/id_dsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.9p1 Ubuntu-3ubuntu0.1
debug1: Remote protocol version 2.0, remote software version OpenSSH_9.0p1 Ubuntu-1ubuntu8
debug1: compat_banner: match: OpenSSH_9.0p1 Ubuntu-1ubuntu8 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 135.125.94.203:22 as 'ubuntu'
debug3: record_hostkey: found key type ED25519 in file /home/mp/.ssh/known_hosts:1
debug3: load_hostkeys_file: loaded 1 keys from 135.125.94.203
debug1: load_hostkeys: fopen /home/mp/.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
debug3: order_hostkeyalgs: have matching best-preference key type [email protected], using HostkeyAlgorithms verbatim
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,[email protected],diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,ext-info-c
debug2: host key algorithms: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],ssh-ed25519,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],rsa-sha2-512,rsa-sha2-256
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: [email protected],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: rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
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: ssh-ed25519
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: SSH2_MSG_KEX_ECDH_REPLY received
debug1: Server host key: ssh-ed25519 SHA256:78sCXM8oOJ0H7mq/mhlVw6N/iLgtGSf6ua3Fr91j0Lo
debug3: record_hostkey: found key type ED25519 in file /home/mp/.ssh/known_hosts:1
debug3: load_hostkeys_file: loaded 1 keys from 135.125.94.203
debug1: load_hostkeys: fopen /home/mp/.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 '135.125.94.203' is known and matches the ED25519 host key.
debug1: Found key in /home/mp/.ssh/known_hosts:1
debug3: send packet: type 21
debug2: ssh_set_newkeys: mode 1
debug1: rekey out after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: ssh_set_newkeys: mode 0
debug1: rekey in after 134217728 blocks
debug1: get_agent_identities: bound agent to hostkey
debug1: get_agent_identities: agent returned 1 keys
debug1: Will attempt key: /home/mp/.ssh/id_rsa RSA SHA256:k1ZxU52fxS6qcGnXNplNGShPZdv4aqFYR30JHvSoeeo agent
debug1: Will attempt key: /home/mp/.ssh/id_ecdsa 
debug1: Will attempt key: /home/mp/.ssh/id_ecdsa_sk 
debug1: Will attempt key: /home/mp/.ssh/id_ed25519 
debug1: Will attempt key: /home/mp/.ssh/id_ed25519_sk 
debug1: Will attempt key: /home/mp/.ssh/id_xmss 
debug1: Will attempt key: /home/mp/.ssh/id_dsa 
debug2: pubkey_prepare: done
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,[email protected],ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected]>
debug1: kex_input_ext_info: [email protected]=<0>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/mp/.ssh/id_rsa RSA SHA256:k1ZxU52fxS6qcGnXNplNGShPZdv4aqFYR30JHvSoeeo agent
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug1: Trying private key: /home/mp/.ssh/id_ecdsa
debug3: no such identity: /home/mp/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /home/mp/.ssh/id_ecdsa_sk
debug3: no such identity: /home/mp/.ssh/id_ecdsa_sk: No such file or directory
debug1: Trying private key: /home/mp/.ssh/id_ed25519
debug3: no such identity: /home/mp/.ssh/id_ed25519: No such file or directory
debug1: Trying private key: /home/mp/.ssh/id_ed25519_sk
debug3: no such identity: /home/mp/.ssh/id_ed25519_sk: No such file or directory
debug1: Trying private key: /home/mp/.ssh/id_xmss
debug3: no such identity: /home/mp/.ssh/id_xmss: No such file or directory
debug1: Trying private key: /home/mp/.ssh/id_dsa
debug3: no such identity: /home/mp/.ssh/id_dsa: No such file or directory
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
[email protected]: Permission denied (publickey).`

密钥是正确的并且 sshd 配置正确（阅读所有以前的 SO 问题以了解此问题）。有任何想法吗？尝试使用 Kitty 从 Windows 连接（改进的 PuTTy）

Ubuntu 服务器 20.04 x64

-rw-r--r-- 1 asdf asdf 1475 Oct 18 15:08 /root/.ssh/authorized_keys

/etc/ssh/sshd_config：

Include /etc/ssh/sshd_config.d/*.conf
Port 22
PermitRootLogin no 
MaxAuthTries 6
PubkeyAuthentication yes
AuthorizedKeysFile      .ssh/authorized_keys
PasswordAuthentication no
ChallengeResponseAuthentication yes
X11Forwarding yes
AcceptEnv LANG LC_*
Subsystem sftp  /usr/lib/openssh/sftp-server

提前致谢

如何从 ssh 服务器中的 ssh 客户端注销所有用户？不只是一个特定的用户，这样我就不必从 ssh 服务器上逐一注销。

我希望传入的 ssh 会话在安全关键服务器不活动时自动断开连接。

我设置了以下设置

TCPKeepAlive no
ClientAliveInterval  30
ClientAliveCountMax 0

我希望 sshd 不会发送 KeepAlive-Packages 由于TCPKeepAlive和ClientAliveCountMax- 并且我的会话将在 30 秒后超时。最重要的是，我认为TCPKeepAlive可以保留其默认值，应该是yes.

我已经检查了这样的现有会话：

root@<server>:/etc/apache2# w
 06:53:51 up 2 days, 21:25,  2 users,  load average: 0,00, 0,00, 0,00
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
_____-ad pts/0    ____________      Do11    6.00s  0.99s  0.00s sshd: _____-admin [priv]
_____-us pts/1    ____________     06:40   13:26   0.02s  0.02s -bash

会话不会超时...

我当然重新启动了 sshd。

root@<server>:/etc/apache2# sshd -T | grep -i "ClientAlive"
clientaliveinterval 30
clientalivecountmax 0

客户端还能发送 KeepAlive-Packages 吗？我无法控制所有连接的客户端版本..

参考资料： https ://www.golinuxcloud.com/disconnect-idle-ssh-session-tcpkeepaliv-linux/ https://secscan.acron.pl/centos7/5/2/13

编辑：TCPKeepAlive yes不会改变行为，会话仍然存在。重新启动 sshd 后，我还启动了一个新会话，以避免在我的 ssh 会话中使用旧设置。

EDIT2：在上面的描述中添加了关键字“incoming”以使其更清楚，我希望我的 ssh 服务器（sshd）在空闲超时后断开连接，因为用户可能会忘记他们打开（和未使用）的 ssh 会话。

EDIT3：仅供参考 - 使用 sshd 版本：

root@<server>:/etc/apache2# dpkg -l openssh-server
Gewünscht=Unbekannt/Installieren/R=Entfernen/P=Vollständig Löschen/Halten
| Status=Nicht/Installiert/Config/U=Entpackt/halb konFiguriert/
         Halb installiert/Trigger erWartet/Trigger anhängig
|/ Fehler?=(kein)/R=Neuinstallation notwendig (Status, Fehler: GROSS=schlecht)
||/ Name           Version            Architektur  Beschreibung
+++-==============-==================-============-=================================================================
ii  openssh-server 1:8.2p1-4ubuntu0.1 amd64        secure shell (SSH) server, for secure access from remote machines
root@<server>:/etc/apache2# sshd -V
unknown option -- V
OpenSSH_8.2p1 Ubuntu-4ubuntu0.1, OpenSSL 1.1.1f  31 Mar 2020

按预期工作

• Debian 10（OpenSSH_7.9p1 Debian-10+deb10u2，OpenSSL 1.1.1d 2019 年 9 月 10 日）*
• Ubuntu 16.04（OpenSSH_7.2p2 Ubuntu-4ubuntu2.8，OpenSSL 1.0.2g 2016 年 3 月 1 日）

*对于 Debian 10，我想比较sshd -T. 不同的选项：casignaturealgorithms, gssapikexalgorithms, hostbasedacceptedkeytypes, hostkeyalgorithms, kexalgorithms, passwordauthentication, permitrootlogin, pubkeyacceptedkeytypes, pubkeyauthoptions,securitykeyprovider

我只设置了passwordauthentication no

我从同一主机连接，唯一的区别是我对有问题的服务器使用了 pubkey 身份验证，而对 Debian 10 服务器使用了密码身份验证。

抱歉，它变长了..它有点变成了一个错误报告..

在 Debian 10 上：

• ClientAliveInterval 10, ClientAliveCountMax 3:每 10 秒ssh -v记录一次消息debug1: client_input_channel_req: channel 0 rtype [email protected] reply 1
• ClientAliveInterval 10, ClientAliveCountMax 0: 会话在 10 秒后断开。

在 Ubuntu 20.04 上：

• ClientAliveInterval 10, ClientAliveCountMax 0:每 10 秒ssh -v记录一次消息debug1: client_input_channel_req: channel 0 rtype [email protected] reply 1

我的家庭网络中有两台机器，我想通过 SSH 连接它们。第一台机器安装了本地 ip192.168.1.23和openssh 远程客户端。第二个安装了本地 ip 192.168.1.169和openssh 服务器。

我在第二台机器上启动服务，

sudo systemctl start ssh

然后我去客户端机器并无法连接，

ssh [email protected]:22
ssh: Could not resolve hostname 0.0.0.0:22: Name or service not known

在上述失败之后，我回到服务器机器并检查了ssh服务状态，表明服务器正在监听 0.0.0.0:22。

1. （0.0.0.0:22）可以吗？
2. 如何通过 SSH 建立该连接？
3. 是ssh和sshd一样的服务吗？

似乎 sshd 发生了微妙的变化，以至于现在 VX Connectbot 不再得到任何响应。这是一个错误吗？新功能？

VX Connectbot（Android 6.0.1 G900PVPS3CQD1 上的 1.7.1-29）可以很好地连接到仿生 sshd，即使它在焦点内核上运行，但没有得到焦点 sshd 的响应。那是怎么回事？

/etc/ssh/sshd_config 在仿生和焦点上是相同的。ufw 没有安装在其中任何一个上。可以从其他 ubuntu 安装中访问任何一个。只是 VX Connectbot 受到了冷落。

我尝试使用仿生 sshd 作为解决方法。如果直接替换为焦点，它将无法启动。它将在仿生 chroot 中运行并接收连接，但从那里我无法通过通常的隧道到达焦点 x11vnc。

还有什么我应该尝试的吗？

我需要为 android 找到一个新的 ssh 客户端吗？有没有捷径可以尝试很多，有没有好地方可以看到好的推荐？

我想设置PubkeyAuthentication no，/etc/ssh/sshd_config但应该排除某人，即：约翰

[已解决][阅读下面的答案]以某种方式 ping IP 地址导致Request timeout，这意味着客户端和服务器端点之间的连接存在问题。感谢user68186帮助我跟踪问题，非常感谢！

我刚刚将 Ubuntu 服务器从 14.04 升级到 16.04。

ssh服务已在服务器中启动。

升级后我无法通过 SSH 连接到服务器。

我正在使用自定义端口，说它是1234

sshd_config logLevel已设置为DEBUG3，最高级别。

我试图检查auth.log文件，但它没有捕捉到任何东西。

已经设置在iptables：

iptables -I INPUT -p tcp --dport 1234 -j ACCEPT

ssh -vvv从显示此消息的客户端执行：

OpenSSH_7.9p1, LibreSSL 2.7.3
debug1: Reading configuration data /Users/username/.ssh/config
debug1: /Users/username/.ssh/config line 74: Applying options for target_server
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 20: Applying options for *
debug1: /etc/ssh/ssh_config line 48: Applying options for *
debug1: /etc/ssh/ssh_config line 52: Applying options for *
debug2: resolve_canonicalize: hostname 192.1.2.3 is address
debug2: ssh_connect_direct
debug1: Connecting to 192.1.2.3 [192.1.2.3] port 1234.
debug1: connect to address 192.1.2.3 port 1234: Operation timed out
ssh: connect to host 192.1.2.3 port 1234: Operation timed out

从客户端执行ssh localhost产生：

Password:
Last login: Wed Feb  5 00:34:54 2020 from 127.0.0.1
Agent pid 22321
Identity added: /Users/username/.ssh/id_rsa (/Users/username/.ssh/id_rsa)

任何线索？

我有一个 256 GB 固态驱动器和一个 2 TB 固态混合驱动器。我在一些网站上看到了他们提出相同问题的参考资料，但我不知道是否替换 Windows。

我需要更换笔记本电脑上的 Windows。而且我的笔记本电脑只有 256 GB 固态硬盘，上面预装了 Windows 10。现在我不知道是否在这个固态驱动器上安装 Ubuntu 18.04 并在完成安装后添加 2 TB 混合驱动器或首先添加 2 TB 混合驱动器并安装 Ubuntu 18.04 然后如何在不分区驱动器的情况下用 Windows 替换 Ubuntu。

安装 Ubuntu 时如何对固态驱动器和混合驱动器进行分区？

附加信息：我正在使用带有 256 GB 固态驱动器和 2 TB 混合驱动器的 Ubuntu，用于机器学习和深度学习。

我有一台运行 Ubuntu 18.04 LTS 的机器，我似乎无法让 SSH 服务器正常工作。

我使用以下方法安装了 SSHServer：

sudo apt install openssh-server

但是当我尝试启动和/或检查状态时，我得到以下信息：

sudo systemctl start sshd

Failed to start sshd.service: Unit sshd.service not found.

.

sudo systemctl status sshd

Unit sshd.service could not be found.

我想我一定是在安装时做错了什么（错字？），所以我尝试再次安装：

sudo apt install openssh-server

我得到：

Reading package lists... Done
Building dependency tree       
Reading state information... Done
openssh-server is already the newest version (1:7.6p1-4ubuntu0.3).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

因此，它似乎已安装，但由于某种原因 Ubuntu 找不到它。

我不确定从这里去哪里，所以欢迎任何建议。

谢谢，

艾伦。