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I wish to set up a configuration on my home network on one of my machines. Namely, I wish to make it feasible to access it via ssh (the machine runs dropbear for ssh) but externally. Here's an "image" of the scenario I wish to achieve:

+---+  +---+  #1: has the static local IP of 1.2.3.4 and listens to port 22 for incoming ssh connections
|#1 |  |#2 |  #2: has a non-static local IP (DHCP given)
+---+  +---+  #3: 3 wishes to connect to #1
  |      |    GATE: the home modem. Its WAN IP is 5.6.7.8
-----  -----        
  \      \                  +------+
   \______\_________________| GATE |
                            +------+
                               |
  +---+                        |
  |#3 |                     __ | _
  +---+                   _(  )_( )__
    |                    (_ internet_)
  -----                    (_) (__)
    \_________________________/

I have followed up and read a similar question here but I am having some trouble setting up my port-forwarding rules on my router's admin web interface and I would like to have some assistance if possible.

In the following image, you can see the options available in order to formulate a port forwarding rule on my modem. Port Forwarding Menu

I have specified the imaginary IP address of #1 (for the sake of simplicity) as 1.2.3.4. But now, I am not completely sure about the following options. Okay lets say that the WAN Host Start/End is the valid range of incoming connections. But then, I am not sure how to proceed with the

  1. WAN START/END ports
  2. LAN START/END ports

The ssh client running on #1 listen's to port 22 and thus, I have added that value there. But I am not once again sure on which of START/END it should fall into.

The manual for the displayed fields on the port forwarding menu says the following about those fields:

Port Forwarding Manual

Thank you in advance.

Update:

After specifying a WAN port range of (START,END):=(1,22) I tried to connect to the machine via:

ssh root@5.6.7.8 -p 22

But I got a timeout:

ssh: connect to host 5.6.7.8 port 22: Connection timed out

ex1led
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1 Answers1

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All settings in the modem / router are correct, and you can ssh from internally to your host meaning that your ssh / dropbear is working. The issue is not your internal network or modem. Unfortunately, your ISP has a hardened firewall not allowing forwarding traffic into your network making it so you cannot access your host externally.

Terrance
  • 43,712