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Tex4066
Asked: 2019-12-12 14:17:38 +0800 CST

Linux QEMU - 来宾可以通过 SSH 连接到主机，但主机可以连接到来宾

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我在通过 SSH 进行 Host-Guest 网络时遇到了一些问题。我在这里查看了许多问题以及 QEMU 的网络文档（https://wiki.qemu.org/Documentation/Networking#How_to_get_SSH_access_to_a_guest），但未能找到答案。

我的来宾 QEMU 实例能够像往常一样通过 SSH 连接到主机。但是，当我尝试从主机通过 SSH 连接到 QEMU 实例时出现ssh_exchange_identification: read: Connection reset by peer错误。

这是我用来启动 QEMU 的命令：

qemu-system-aarch64 -M virt -m 32768 -cpu cortex-a72 \
  -kernel $VMLINUZ \
  -initrd $INITRD \
  -append 'root=/dev/vda2' \
  -drive if=none,file=$COW,format=qcow2,id=hd \
  -device virtio-blk-pci,drive=hd \
  -netdev user,id=mynet \
  -device virtio-net-pci,netdev=mynet \
  -nographic \
  -device e1000,netdev=net0 \
  -netdev user,id=net0,hostfwd=tcp::5555-:22

启动 QEMU 后，我尝试使用以下命令 SSH 并获得以下输出：

<*user*>@<*hostname*>:~$ ssh localhost -p 5555 -vvv
OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n  7 Dec 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "localhost" port 5555
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to localhost [127.0.0.1] port 5555.
debug1: Connection established.
debug1: identity file /home/<*user*>/.ssh/id_rsa type 0
debug1: key_load_public: No such file or directory
debug1: identity file /home/<*user*>/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/<*user*>/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/<*user*>/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/<*user*>/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/<*user*>/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/<*user*>/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/<*user*>/.ssh/id_ed25519-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
ssh_exchange_identification: read: Connection reset by peer

非常感谢您对此的任何帮助！

编辑：

两台机器都运行 Ubuntu 18.04。

主持人：

Linux trace5 5.0.0-37-generic #40~18.04.1-Ubuntu SMP Thu Nov 14 12:06:39 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

来宾：

Linux qemu-trace 5.2.0-050200-generic #201907072331 SMP Sun Jul 7 23:48:00 UTC 2019 aarch64 aarch64 aarch64 GNU/Linux

来宾正在运行sshd，

ps -ef | grep '[s]shd'
root 616 1 0 Dec11 ? 00:00:00 /usr/sbin/sshd -D

/var/log/auth.log如果有帮助，这是对客人的摘录。我正在阅读身份验证失败，但不确定这意味着什么，因为时间戳与我的主机 ssh-ing 的时间不一致：

Dec 11 18:43:17 qemu-trace sshd[1547]: Server listening on 0.0.0.0 port 22.
Dec 11 18:43:17 qemu-trace sshd[1547]: Server listening on :: port 22.
Dec 11 18:43:17 qemu-trace sudo: pam_unix(sudo:session): session closed for user root
Dec 11 18:45:30 qemu-trace systemd-logind[610]: New seat seat0.
Dec 11 18:45:33 qemu-trace sshd[617]: Server listening on 0.0.0.0 port 22.
Dec 11 18:45:33 qemu-trace sshd[617]: Server listening on :: port 22.
Dec 11 18:46:18 qemu-trace login[620]: pam_unix(login:session): session opened for user trace by LOGIN(uid=0)
Dec 11 18:46:19 qemu-trace systemd-logind[610]: New session 1 of user trace.
Dec 11 18:46:19 qemu-trace systemd: pam_unix(systemd-user:session): session opened for user trace by (uid=0)
Dec 11 19:17:01 qemu-trace CRON[675]: pam_unix(cron:session): session opened for user root by (uid=0)
Dec 11 19:17:02 qemu-trace CRON[675]: pam_unix(cron:session): session closed for user root
Dec 11 19:20:13 qemu-trace systemd-logind[605]: New seat seat0.
Dec 11 19:20:17 qemu-trace sshd[616]: Server listening on 0.0.0.0 port 22.
Dec 11 19:20:17 qemu-trace sshd[616]: Server listening on :: port 22.
Dec 11 19:22:33 qemu-trace login[621]: pam_unix(login:auth): check pass; user unknown
Dec 11 19:22:33 qemu-trace login[621]: pam_unix(login:auth): authentication failure; logname=LOGIN uid=0 euid=0 tty=/dev/ttyAMA0 ruser= rhost=
Dec 11 19:22:37 qemu-trace login[621]: FAILED LOGIN (1) on '/dev/ttyAMA0' FOR 'UNKNOWN', Authentication failure
Dec 11 19:22:49 qemu-trace login[621]: pam_unix(login:session): session opened for user trace by LOGIN(uid=0)
Dec 11 19:22:49 qemu-trace systemd-logind[605]: New session 1 of user trace.
Dec 11 19:22:50 qemu-trace systemd: pam_unix(systemd-user:session): session opened for user trace by (uid=0)
networking ssh

3 个回答

  1. Best Answer

    我能够找到问题；这是我的 QEMU 命令的问题。启动 QEMU 的新命令：

    qemu-system-aarch64 -M virt -m 32768 -cpu cortex-a72 \
  -kernel $VMLINUZ \
  -initrd $INITRD \
  -append 'root=/dev/vda2' \
  -drive if=none,file=$COW,format=qcow2,id=hd \
  -device virtio-blk-pci,drive=hd \
  -netdev user,id=mynet \
  -device virtio-net-pci,netdev=mynet,hostfwd=tcp::2222-:22 \
  -nographic

    然后我可以从主机 SSH：

    <user>@<host>:~$ ssh <host>@localhost -p 2222
<user>@localhost's password: 
Welcome to Ubuntu 18.04.2 LTS (GNU/Linux 5.2.0-050200-generic aarch64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

Last login: Thu Dec 12 14:31:28 2019
<user>@<guest>:~$
    • 2

  2. 您有一个条目/etc/hosts.deny阻止ssh登录。

    例如，这将拒绝来自所有远程系统的所有服务的入站连接尝试：

    ALL : ALL

    在我的 Debian 系统上，该文件/var/log/auth.log包含ssh拒绝登录的原因。你的客人也会有类似的东西。hosts.deny与我在此处显示的示例条目对应的条目看起来像这样

    Dec 11 22:54:40 vmguest sshd[30741]: refused connect from 192.168.1.2 (192.168.1.2)
    • 0

  3. 服务是否sshd在您的客户操作系统上运行？qemu只需将您的包从 转发localhost:5555到guesthost:22，如果您的来宾操作系统上的端口 22 上没有sshd服务侦听，它将是Connection reset by peer.

    • 0

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