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pszabo's avatar
pszabo
Aspirant
Nov 18, 2022

NETGEAR Nighthawk(R) X4S R7800 - Can not properly reconnect to ISP's cable-modem

Hi All! I've problem with my NETGEAR Nighthawk(R) X4S R7800 router. My router can not reconnect properly to the internet after my ISP's Cable Modem is restartting. Every time after modem resta...
FURRYe38's avatar
FURRYe38
Guru
Nov 18, 2022

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?
Be sure your using a good quality LAN cable between the modem and router. CAT6 is recommended. 

 

Has a power off for 1 minute then back ON with the ISP modem and router been performed since last update?
Be sure to restart your network in this sequence:
Turn off and unplug modem.
Turn off router and computers.
Plug in and turn on modem. Wait 2 minutes for it to connect.
Turn on the router and wait 2 minutes for it to connect.
Turn on computers and rest of network.

 

Has a factory reset and setup from scratch been performed since last FW update? 

A complete pull of the power adapters for a period of time after the factory reset then walk thru the setup wizard and setup from scratch.

  • pszabo's avatar
    pszabo
    Aspirant
    Nov 22, 2022

    Hi FURRYe38,

     

    Thanx for your reply. Here I'm answering for your questions inline.


    "What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too?"

    There is no any other label on the outside just as I wrote previously:  "vodafone   TG3442DE"
    As I know it's a  "Arris Touchstone TG3442DE"  modem


    "Be sure your using a good quality LAN cable between the modem and router. CAT6 is recommended. "

    I'm using Cat5e cables since years without problem.

     

    "Has a power off for 1 minute then back ON with the ISP modem and router been performed since last update?"

    Yes, no help.


    "Be sure to restart your network in this sequence:
    Turn off and unplug modem.
    Turn off router and computers.
    Plug in and turn on modem. Wait 2 minutes for it to connect.
    Turn on the router and wait 2 minutes for it to connect.
    Turn on computers and rest of network."

    I did it several times.

     

    "Has a factory reset and setup from scratch been performed since last FW update? "

    Yes


    "A complete pull of the power adapters for a period of time after the factory reset then walk thru the setup wizard and setup from scratch."

    I've done it already, no help.

    You've to know, I'm an IT engineer (SW developer) and I'm over of all the basic things. I've used the R7800 via my ISP's older modem (a Compal modem for 500mbits), and I did not experience any issue. If the modem has been restarted sometime, I do not even realize it.
    But now, with this vodafone / Arris modem which I got for the 1000mbits subscription I've got this issue. 

    Due to some ISP side problem the modem restarted itself very often (1-2-3 times / day) and every time I had to use the Release than Renew feature to get proper internet connection. Of course if I reboot the R7800 that also solved the problem.

    Even after couple hours later the router does not properly reconnect -by itself-.  (only manual relese/renew or reboot helps)

    The strange thing is that my old WNDR 3400 (with dd-wrt) does not produce such problem, that is simply reconnecting after the modem restarts. (no need to release/renew or reboot)

     

     

     

    • FURRYe38's avatar
      FURRYe38
      Guru
      Nov 22, 2022

      Your ISP Modem already has a built in router and wifi. This would be a double NAT (two router) condition which isn't recommended. This would be a double NAT condition which isn't recommended. https://kb.netgear.com/30186/What-is-Double-NAT
      https://kb.netgear.com/30187/How-to-fix-issues-with-Double-NAT
      Couple of options,
      1. Configure the modem for transparent bridge or modem only mode. Then use the NG router in router mode. You'll need to contact the ISP for help and information in regards to the modem being bridged correctly.
      2. If you can't bridge the modem, disable ALL wifi radios on the modem, configure the modems DMZ/ExposedHost or IP Pass-Through for the IP address the NG router gets from the modem. https://kb.netgear.com/25891/DMZ-on-NETGEAR-routers
      https://kb.netgear.com/24086/How-do-I-set-up-a-default-DMZ-server-on-my-Nighthawk-router
      3. Or disable all wifi radios on the modem and connect the NG router to the modem, LAN to LAN configure AP mode on the NG router.
      https://kb.netgear.com/20927/How-do-I-change-my-NETGEAR-router-to-AP-mode

       

      Might try option #2 first...

      • pszabo's avatar
        pszabo
        Aspirant
        Nov 22, 2022

        The modem is configured to work in bridge mode as I wrote at my original post!

        ISP configured it to me as this config is restricted from the end users.

        With bridge mode it's WiFi is also disabled. (That also not configurable by the end users)

         

        My configuration works as you describe in Option #1.
        Option #2 also not useful, as the modem's admin page is very-very restricted by the ISP.

        (There is no such option as DMZ/ExposedHost or IP Pass-Through.)
        I do not want to degrade the R7800 to act as a simple AP, so Option #3 is also not applicable.

         

        My question in a simpler form: why the R7800 can not reconnect properly, while the WNDR 3400 can?   (Very same modem, with the very same modem configuration)

        I'd not be not too happy if I'd need to put ddwrt -or some other custom router firmware- to my R7800.