前台的 ssh 隧道适用于 mysql 主机 localhost，但后台的 ssh-tunnel 适用于 mysql 主机 127.0.0.1 [英] ssh tunnel in foreground works for mysql host localhost but ssh-tunnel in background works for mysql host 127.0.0.1

问题描述

我在这里尝试做的是将所有连接转发到第一台机器上的 localhost 3306 端口到第二台机器上的 localhost 3306 端口.因此，如果您在第一台机器上连接到 mysql，它就像您正在连接一样在机器二上.

What I am trying to do here is forward all connections to localhost on machine-one on port 3306 to machine-two on localhost on port 3306. So if you are connecting to mysql on machine-one it acts like you are connecting on machine two.

我认为 ssh 隧道应该转发特定端口上的流量，而不是像将我登录到另一台机器一样.(就像在这里做的那样)我尝试过在@machine-two-hostname.com"之前没有admin"，这也做同样的事情.正如标题所说，在后台运行它不会让我在本地主机"上连接，当我尝试在绑定地址已在使用"的相同端口上设置另一个 ssh 隧道时，它确实给了我一条新消息，我是怀疑我在下面运行的命令也不起作用，但它只是将我登录到另一台机器而不是连接端口.

I thought an ssh tunnel was supposed to forward the traffic on a specific port not act like it is logging me into the other machine. (like it is doing here) I have tried without the "admin" before "@machine-two-hostname.com" and that does the same thing. As the title says running this in the background doesn't let me connect on "localhost" it does give me a new message when I try to set up another ssh tunnel on the same ports that "bind address already in use" I'm suspicious that the commands I am running below aren't working either but that it is just logging me into the other machine and not connecting the ports.

admin@machine-one:~$ ssh -L 3306:localhost:3306 [e-mail]
Linux machine-two 4.9.0-6-amd64 #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) x86_64

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/\*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Wed Jun 20 11:16:07 2018 from 172.31.93.22
admin@machine-two:~$ mysql -uroot -proot-pass
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 19
Server version: 10.1.26-MariaDB-0+deb9u1 Debian 9.1

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> \q
Bye
admin@machine-two:~$ exit
logout
Connection to machine-two-hostname.com closed.
admin@machine-one:~$ ssh -fN -L 3306:localhost:3306 [e-mail]
admin@machine-one:~$ mysql -uroot -proot-pass
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2 "No such file or directory")

后台运行:

admin@machine-one:~$ ssh -fN -L 3306:localhost:3306 machine-two-hostname.com
admin@machine-one:~$ mysql -uroot -proot-pass -hlocalhost
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2 "No such file or directory")

UPDATE 在后台运行时，当我使用 127.0.0.1 而不是 localhost 时，mysql 连接有效，为什么?

UPDATE when running in the background the mysql connection works when I use 127.0.0.1 instead of localhost, why?

admin@machine-one:~$ mysql -uroot -proot-pass -hlocalhost
ERROR 2002 (HY000): Cant connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2 "No such file or directory")
admin@machine-one:~$ mysql -uroot -proot-pass -h127.0.0.1
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 20
Server version: 10.1.26-MariaDB-0+deb9u1 Debian 9.1

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> 

推荐答案

在这里找到答案:使用SSH tunel时无法通过socket连接到本地MySQL服务器

"在 Unix 上，MySQL 程序特别对待主机名 localhost，与其他基于网络的程序相比，它的处理方式可能与您期望的不同.对于到 localhost 的连接，MySQL 程序尝试通过以下方式连接到本地服务器使用 Unix 套接字文件.即使提供了 --port 或 -P 选项来指定端口号，也会发生这种情况.要确保客户端与本地服务器建立 TCP/IP 连接，请使用 --host 或 -h指定主机名值 127.0.0.1，或本地服务器的 IP 地址或名称.您还可以使用 --protocol=TCP 选项显式指定连接协议，甚至对于 localhost.例如:

"On Unix, MySQL programs treat the host name localhost specially, in a way that is likely different from what you expect compared to other network-based programs. For connections to localhost, MySQL programs attempt to connect to the local server by using a Unix socket file. This occurs even if a --port or -P option is given to specify a port number. To ensure that the client makes a TCP/IP connection to the local server, use --host or -h to specify a host name value of 127.0.0.1, or the IP address or name of the local server. You can also specify the connection protocol explicitly, even for localhost, by using the --protocol=TCP option. For example:

shell> mysql --host=127.0.0.1
shell> mysql --protocol=TCP

来自 mysql 文档:https://dev.mysql.com/doc/refman/8.0/en/connecting.html

from mysql documentation: https://dev.mysql.com/doc/refman/8.0/en/connecting.html

所以这在我在后台设置隧道后有效:

So this works after I set up the tunnel in the background:

admin@machine-one:~$ mysql -uroot -proot-pass --protocol=TCP -hlocalhost
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 23
Server version: 10.1.26-MariaDB-0+deb9u1 Debian 9.1

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> 

但是我想知道如果我在前台的 ssh 隧道真的按照它应该的方式工作，它是否应该让您登录到另一台机器?

I would like to know however if my ssh tunnel in the foreground is actually working the way it should be, is it supposed to log you into the other machine?

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