无法从 Google Compute Instance ftp 客户端以主动模式建立外部 ftp 服务器连接

Question

我找到了解决方案！在 Google 云网络下无法与外部 ftp 服务器建立主动 ftp 连接。

The big problem is that when a client program is using network address translation to hide behind a routing device on an internal network, when using PORT the client tells a server on the external network to connect to an address on the client's internal network.  I.e., from the example above:

Client: PORT 192,168,1,2,7,138

解决方案：

The solution depends from the network administrator of the client network to use high-quality network address translation software.  Devices can keep track of FTP data connections, and when a client on a private network uses "PORT" with an internal network address, the device should dynamically rewrite the packet containing the PORT and IP address and change the address so that it refers to the external IP address of the routing device.  The device would then have to route the connection incoming from the remote FTP server back to the internal network address of the client.  I.e., from the example above we had:

Client: PORT 192,168,1,2,7,138

When the packet containing this PORT reaches the routing device, it should be rewritten like this, assuming the external address is 17.254.0.26:

Client: PORT 17,254,0,26,7,138

The remote server would then attempt to connect to 17.254.0.26:1930.  The routing device in this example would then forward all traffic for this connection to and from the client address at 192.168.1.2:1930.

更多细节这里

我不知道在 google 环境中是否可行这种解决方案。

针对 google cloud 找到的唯一解决方案（目前）：破解 ftp 客户端（在我的情况下很简单：ruby）强制在 ftp PORT 命令中发送真实的外部网络地址。

欢迎提出其他更好的解决方案！

Answer 1

我找到了解决方案！在 Google 云网络下无法与外部 ftp 服务器建立主动 ftp 连接。

The big problem is that when a client program is using network address translation to hide behind a routing device on an internal network, when using PORT the client tells a server on the external network to connect to an address on the client's internal network.  I.e., from the example above:

Client: PORT 192,168,1,2,7,138

解决方案：

The solution depends from the network administrator of the client network to use high-quality network address translation software.  Devices can keep track of FTP data connections, and when a client on a private network uses "PORT" with an internal network address, the device should dynamically rewrite the packet containing the PORT and IP address and change the address so that it refers to the external IP address of the routing device.  The device would then have to route the connection incoming from the remote FTP server back to the internal network address of the client.  I.e., from the example above we had:

Client: PORT 192,168,1,2,7,138

When the packet containing this PORT reaches the routing device, it should be rewritten like this, assuming the external address is 17.254.0.26:

Client: PORT 17,254,0,26,7,138

The remote server would then attempt to connect to 17.254.0.26:1930.  The routing device in this example would then forward all traffic for this connection to and from the client address at 192.168.1.2:1930.

更多细节这里

我不知道在 google 环境中是否可行这种解决方案。

针对 google cloud 找到的唯一解决方案（目前）：破解 ftp 客户端（在我的情况下很简单：ruby）强制在 ftp PORT 命令中发送真实的外部网络地址。

欢迎提出其他更好的解决方案！

无法从 Google Compute Instance ftp 客户端以主动模式建立外部 ftp 服务器连接

答案1

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