Accessing the modem through the router

Hello,
I have a modem (O2 Box 6741, static IP: 182.168.1.1) connected via LAN (WAN is without any funktion) to the WAN of the router (with OpenWRT 21.02.1, static IP: 192.168.2.1).

I followed this manual: https://openwrt.org/docs/guide-user/network/wan/access.modem.through.nat, but it doesn't work. I set IPv4 address: 192.168.1.2

After that, I tried Interface + Firewall @lan Even without any sucsess.

What can I do?
Bebbi

If you're talking about access to the modem's management GUI, this is how I did it...

The modem's IP address is 192.168.254.254

  1. Created a new WAN interface called MODEM. No DHCP turned on and selected static IP as the protocol.

  2. IPv4 address set to 192.168.254.253

  3. Netmask set to 255.255.255.0

  4. Gateway IP set to 192.168.254.254

  5. Added the MODEM WAN connection to the WAN firewall zone.

  6. Clicked on Restart for the MODEM interface. *

  7. Entered 192.168.254.254 in the browser address bar.

  8. Got the modem login prompt.

  9. Logged in, and was able to access all functions.

  • Click on Stop for the WAN interface first if there are issues with both WAN and MODEM interfaces running.

It should just work (with OpenWrt at basic default settings) to connect to the OpenWrt LAN then send your browser to 192.168.1.1. The default route (for anything other than 192.168.2.0/24) of the OpenWrt box is to its WAN port and thus it will go to the modem.

My Modem has no WAN. Should I use WAN however (No. 5)?

@mk24: I don't understand, what you say. Do you refer to OldNavyGuy?

You're using the O2 box as DSL to Ethernet (with routing to 192.168.1.1) then routing that network again in an OpenWrt box to 192.168.2.1, right?

The DSL line is the O2 box's WAN. The "WAN" port on the back is if you had a different type of ISP and not using the integral DSL modem. So leave that port unconnected in your usage.

You're using the O2 box as DSL to Ethernet (with routing to 192.168.1.1) then routing that network again in an OpenWrt box to 192.168.2.1, right?

Yes.

So, the cable connecting MODEM LAN ans ROUTER WAN.

Next time:

The modem's IP address is 192.168.1.1

  1. Created a new WAN interface called MODEM. No DHCP turned on and selected static IP as the protocol.
  2. IPv4 address set to 192.168.1.2
  3. Netmask set to 255.255.255.0
  4. Gateway IP set to 192.168.1.1
  5. Added the MODEM LAN connection to the LAN firewall zone.
  6. Clicked on Connect for the MODEM interface.
  7. Entered 192.168.1.1 in the browser address bar.
    Got **nothing
  8. Entered 192.168.1.2 in the browser address bar.
    10 Got openWRT
  9. Entered a URL in the browser address bar: no internet
  10. Reboot the modem
  11. Entered a URL in the browser address bar: internet



When you attach the OpenWrt WAN network to the modem, that makes it configure a 192.168.1.X network on the WAN port. You don't have to add another. Do not add another. This is one of those cases where default configuration (other than changing the LAN IP to 192.168.2.1 so as not to conflict with the WAN network) will suit your needs.

First though I would connect the modem (LAN) directly to a PC, let the PC obtain a 192.168.1.X IP, and confirm the modem accepts login at 192.168.1.1.

Re-read the post.

Should be WAN instead of LAN.

You missed step 6.

I stopped the WAN interface, and did a restart on the MODEM interface.

When done, stopped the MODEM interface, and did a restart on the WAN interface.

Never had an issue.

But it didn't work, so I looked for a manual and found https://openwrt.org/docs/guide-user/network/wan/access.modem.through.nat Using der Modem WLAN, I achieve 192.168.1.1

You mean, that OpenWRT on the router makes do somethink, that I don't understand?

That's kill the internet connection, but doen't enable a connection to the modem.

You do a Restart on the MODEM interface to connect.

If you have an issue doing that while the WAN interface is connected, do a Stop on that interface first.