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无法从外部连接 Ubuntu Server ssh

tag-icon • tag-icon networking server ssh iptables connection
无法从外部连接 Ubuntu Server ssh

我们的台式机上安装了 ubuntu 服务器。它通过以太网端口连接调制解调器。我们可以通过网络内部的 ssh 访问它。但不能从外部访问。

以下是我们目前所做的工作：

当我从装有 ubuntu 服务器的局域网运行时ssh [email protected]

[email protected]'s password:
Welcome to Ubuntu 20.04.4 LTS (GNU/Linux 5.4.0-104-generic x86_64)

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

  System information as of Thu 10 Mar 2022 08:45:36 AM UTC

  System load:  0.07               Processes:                166
  Usage of /:   2.0% of 438.13GB   Users logged in:          1
  Memory usage: 2%                 IPv4 address for docker0: 172.17.0.1
  Swap usage:   0%                 IPv4 address for enp3s0:  192.168.1.200
  Temperature:  50.0 C

 * Super-optimized for small spaces - read how we shrank the memory
   footprint of MicroK8s to make it the smallest full K8s around.

   https://ubuntu.com/blog/microk8s-memory-optimisation

0 updates can be applied immediately.

但是当我从我们的 wifi 外面跑步时。ssh -v [email protected]

OpenSSH_for_Windows_8.1p1, LibreSSL 3.0.2
debug1: Reading configuration data C:\\Users\\MaviArge/.ssh/config
debug1: Connecting to 213.XXXXXXX [213.XXXXXXX] port 22.
debug1: connect to address 213.XXXXXXX port 22: Connection timed out
ssh: connect to host 213.XXXXXXX port 22: Connection timed out

当我ping 213.XXXXXXX 从外面跑来的时候

Pinging 213.XXXXXXX with 32 bytes of data:
Reply from 213.XXXXXXX: bytes=32 time=67ms TTL=46
Reply from 213.XXXXXXX: bytes=32 time=97ms TTL=46
Reply from 213.XXXXXXX: bytes=32 time=107ms TTL=46
Reply from 213.XXXXXXX: bytes=32 time=124ms TTL=46

Ping statistics for 213.XXXXXXX:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 67ms, Maximum = 124ms, Average = 98ms

在网上看到这个命令sudo lsof -i:22和输出：

sudo lsof -i:22
COMMAND  PID     USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
sshd    3290     root    4u  IPv4  38814      0t0  TCP maviarge:ssh->host-213.XXXXXXX.reverse.superonline.net:58124 (ESTABLISHED)
sshd    3375 maviarge    4u  IPv4  38814      0t0  TCP maviarge:ssh->host-213.XXXXXXX.reverse.superonline.net:58124 (ESTABLISHED)
sshd    4057     root    3u  IPv4  71589      0t0  TCP *:ssh (LISTEN)
sshd    4057     root    4u  IPv6  71591      0t0  TCP *:ssh (LISTEN)
sshd    5662     root    4u  IPv4  74261      0t0  TCP maviarge:ssh->host-213.XXXXXXX.reverse.superonline.net:60472 (ESTABLISHED)
sshd    5746 maviarge    4u  IPv4  74261      0t0  TCP maviarge:ssh->host-213.XXXXXXX.reverse.superonline.net:60472 (ESTABLISHED)

另外进行 nmap 扫描：

Starting Nmap 7.92 ( https://nmap.org ) at 2022-03-10 05:17 EST
Nmap scan report for host-213.XXXXXXX.reverse.superonline.net (213.XXXXXXX)
Host is up (0.14s latency).
Not shown: 96 closed tcp ports (reset)
PORT     STATE    SERVICE
22/tcp   filtered ssh
25/tcp   filtered smtp
5060/tcp filtered sip
5432/tcp open     postgresql

Nmap done: 1 IP address (1 host up) scanned in 2.08 seconds

sudo ufw status

Status: active

To                         Action      From
--                         ------      ----
22/tcp                     ALLOW       Anywhere
22                         ALLOW       Anywhere
22/tcp (v6)                ALLOW       Anywhere (v6)
22 (v6)                    ALLOW       Anywhere (v6)

答案1

我在这里看到两个可能的问题：

  • 路由器上的防火墙：当您将端口 22 重定向到网关的 NAT 时，超时表示没有从我们的路由器返回 IP 数据包。您可能还需要检查防火墙配置中是否需要打开 TCP 上的端口 22。
  • （由于您编辑了页面，因此可能不再是此问题）Routeback 问题：某些路由器禁止从同一接口传入和传出流量。这意味着您可能无法使用与您的服务器相同的网络的公共 IP 加入端口 22。您可以通过尝试从另一个 ISP（例如从您的家中）连接到您的服务器来检查这是否是 routeback 问题。

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