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stuyboy's avatar
stuyboy
Tutor
Dec 26, 2021

LM1200 in Router Mode: Port Forwarding or DMZ working for you?

LM1200 on Verizon, using alongwide WAN/Cable as cellular backup.

Unfortunately using in Router mode as I'm on Verizon (Bridge works fine).

 

Hosting a few servers, so I'd like to forward ports (443) to my primary router (Edgerouter X)

 

I tried using Port Forwarding rules as well as DMZ (pointing to the DHCP assigned address for my Edgerouter ie 192.168.5.40, making sure to configure DHCP so it can only assign one address to my Edgerouter).

 

On Cellular, I don't expect to reach my servers, but even on Broadband, the DMZ and Port Forwarding rules don't seem to work.  Obviously my Edgerouter has the appropriate port forwarding IPs configured.

 

Anyone get the LM1200 to port forward "twice" in Router mode?  

 

My backup plan is to switch to a TMo plan, hopefully allowing me to use LM1200 in Bridge mode, making this all much simpler.

 

 

4 Replies

  • Did you ever get your port forwarding to work?

     

    I am using the LM1200 with Verizon also.  I have a TP-Link router connected to the LM1200.  I have set up my port forwarding on the TP-Link, but I can't enter the IP of my LAN device in the LM1200 because the IP range is different.  192.168.5.x for the modem, 192.168.0.x for the router LAN.  

     

    I couldn't get my router to stay online when the modem was in Bridge mode, but it works fine in Router mode.  I had hoped to stay in Bridge mode to avoid this type conflict, but no such luck.

    • stuyboy's avatar
      stuyboy
      Tutor

      No, I tried all sorts of combinations to port forward, but didn't run into this IP problem as you allude to.  I think I was also trying to port forward twice, through my router which was itself configured to port forward to another server on my LAN.  Obviously I wasn't expecting it to work well when on LTE, but my problem is that it wouldn't work while on broadband either. 

       

      In the end I signed up for a small plan with Net10 wireless, which does not rely on Verizon, and got it to barely work.  But in my case, it's a backup connection anyway, so didn't matter.  But I would have preferred to be on Verizon (along with all my other devices), and that problem is STILL not solved, check the other thread for details.

      • adelva's avatar
        adelva
        Aspirant

        This is an old post and an old device, but just for others looking for this information, I discovered that the DMZ will only forward packets that have the destination IP match the IP of the device being forwarded to. All other packets are dropped.

         

        For example, under Linux you can do:

         

        $ route add -host 192.168.5.2/32 gw 192.168.2.190

        $ ping 192.168.5.2 # this works now

        $ ssh 192.168.5.2 # this works now

         

        Where 192.168.5.2 is the NAT IP you configured in your DMZ config, and 192.168.2.190 is one of the WAN IPs your LM1200 got.

         

        If you were expecting it to forward all packets from e.g. 192.168.2.190 to 192.168.5.2 like the web ui suggests it will, it appears not to do this.

         

        This feature is still very useful if you have a single device behind the modem that you need to be able to access and can configure a special route. I'm using it because my "broadband WAN" port is actually on my LAN, and otherwise the NAT'ing of the device behind the modem would be inaccessible.