IP Forwarding


#1

I have the following setup (on a Balance 30)

  • WAN1: BT ADSL - Netgear DG834 (in Modem Mode), PPPoE connection
  • WAN2: O2 ADSL - Netgear DG834 (in Modem Mode), PPPoE connection
  • WAN3: Tooway Satellite - Satellite Modem, provides public IP to B30

Currently all of my WAN connections are running NAT.

The problem is that I can’t connect to my modem’s GUI’s from my LAN (this has been promised as a feature as per here: https://forum.peplink.com/threads/198 but hasn’t arrived yet).

So my thoughts are to change WAN1 & WAN2 to IP Forwarding and change the 2 x Netgear DG834 devices back into router mode so they do NAT. Is my understanding correct that this would work, I assume setting a WAN interface on the B30 to IP Forwarding disables NAT (obviously I want to avoid double-NAT).

I also assume my proposed setup will complicate any inbound port forwarding I need.

Any thoughts/comments appreciated.


#2

When the modem is bridged to the Peplink, then the layer 3 (IP) between the Peplink and the modem UI is not established. However if the modem has a wifi as well, then you might be able to access it that way.

You can do this; have each modem handle the PPPoE, and then each does NAT and the Peplink does static or DHCP to each. Now if each of those NAT segments has a different network space (eg. 192.168.31.x and 192.168.32.x), then you can access the modem GUI from inside the LAN (192.168.31.1 and 192.168.32.1). The downside of this is if you need to do port forwarding, then it needs rules in both the modem and the Peplink.


#3

Heathy65-
Can you try the following experiment:

Leave everything set up as it currently is. Take a PC and statically assign it an IP address of 192.168.0.2 with a subnet mask of 255.255.255.0 on its Ethernet interface. Then plug it directly in to one of the additional LAN ports on your DG834 modem. Next, open a browser and see if you can access the modem at 192.168.0.1

I’m curious to see if this will work…

Thanks -Tim


#4

Hi Tim, thanks for your thoughts.

I’ve tried that in the past and it did work. Actually I did it in a different way (I didn’t want to over complicate my setup explanation in my 1st post). I actually have a LAN switch (Cisco Catalyst 3550) between my B30 WAN connections and the 3 x ADSL/Sat modems. Each WAN has its own separate VLAN so I configured 802.11d trunking on my Mac (on my LAN) and then could connect to the modems directly from my Mac as expected. Of course this is a rather complicated setup and it’d be a whole lot simpler to be able to connect from the B30 LAN to the modems on the WAN side with them using PPPoE (and no trunking VLANs, or connecting directly to the modems as you suggest).

As an alternative using IP forwarding on the B30 and configuring the ADSL devices as routers (rather than modems) is a solution but makes port forwarding messy.


#5

Okay, that tells me that the modem is still listening on 192.168.0.1 even though it is in bridge mode.

Can you try pinging this address on WAN1 or WAN2 from within the Balance?


#6

@Healthy65, You can turn WAN1 and WAN2 to IP forwarding. With this setup, the modems will need to handle all NAT and also the Inbound Port Forwarding. Also, you have to add the Static Route to modems to let its how to route to your LAN subnet. For example, the Modem IP is 192.168.0.1/24, you will configure the WAN of Peplink to 192.168.0.2/24. The Peplink LAN is 192.168.100.0/24. In this situation, you need to add a static route in modem - “192.168.100.0/24 via 192.168.0.2”