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mercilesskiller's avatar
mercilesskiller
On our wavelength
2 years ago
Solved

Modem Mode on Hub 4 won't work - no DHCP/WAN connection (but connection fine in Router Mode)

Hi All

I've had an issue with my Hub 4 come up overnight which I'm wondering if anyone has any ideas around. 

I have a 500mb Virgin connection which works fine when the Hub 4 is in router mode. It has been operating however in Modem Mode, connected to a Netgear Raxe300 NightHawk with no problem for months.

I woke up this morning with no connection. Hub 4 light was still green. When looking on the Netgear router, there was no IP address coming on the WAN port of the Netgear (DHCP didn't seem to be working). Reset Hub 4, nothing. Tried different cables, nothing, reset Netgear, nothing. Couldn't access the Hub 4 in modem mode through the Netgear because that internal IP (192.168.100.X) wasn't coming through DHCP. 

I manually set a static IP on the WAN port of the Netgear to 192.168.100.13/255.255.255.0 with default gateway as .1 - through this I COULD then connect to the UI for the Hub 4 (success!). However, not the internet... I took some screenshots of the admin page on the Hub 4 but nothing seemed to suggest an issue. Note in the last screenshot there's no IP/WAN information though when in router mode, on this page it does show a WAN connection status.

For now I've flipped it back into Router Mode so accessing the internet via the Hub 4 but I really need to get the router working again in Modem Mode. Any ideas? It almost feels like there's been some firmware update that's broken modem mode? It sounds like for whatever reason when in modem mode, it just won't connect externally nor will it give an internal IP to the Netgear - did plenty of "leaving it off for 2 minutes" and reconnecting but no luck.

Thanks!

 

 

 

 

  • Roger_Gooner's avatar
    Roger_Gooner
    2 years ago

    The correct procedure is to power on the hub first and then the router as doing it this way ensure that the hub's modem goes though its complicated initialisation with the CMTS and gets the data it needs from the DHCP server for the WAN IP address and routing table. When you then power on the router all the work has been done by the modem and the router will get its WAN IP address as the modem is acting as a bridge. If you power on the router before the hub there is the risk that the router will fail to get its IP address and/or begin to prematurely assign IP addresses to connected devices, which is why a power recycle of the router will be needed to get it to work.

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  • mercilesskiller's avatar
    mercilesskiller
    On our wavelength
    2 years ago

    Weirdly on the last one, all the "Thu" entries are from 1970. The other days are all from this week (week of 4th December). The problem occurred both overnight on the 4th to the 5th and 5th to the 6th.

  • Roger_Gooner's avatar
    Roger_Gooner
    Alessandro Volta
    2 years ago

    Your log shows repeated failures of your modem and CMTS to communicate. Unless there is an area fault you need a tech to come round.

  • mercilesskiller's avatar
    mercilesskiller
    On our wavelength
    2 years ago

    Weird - no faults show on status pages around my area... Should I expect this to just keep failing every single night? I suppose I'll see what happens tonight and see if it happens again first. 3 times in a row and then it does feel like too much of a coincidence..

  • legacy1's avatar
    legacy1
    Alessandro Volta
    2 years ago

    Copy your router Netgear WAN MAC to a PC NIC when router fails connect PC to hub in place of router without rebooting the hub.

    Possibly a DHCP problem with VM but in order to see that with your router you need a switch with port mirroring to see it happening to a PC NIC using a USB to Ethernet adapter with Wireshark.

  • mercilesskiller's avatar
    mercilesskiller
    On our wavelength
    2 years ago

    Not really sure how I do this because:

    1) The problem happens overnight when asleep. 

    2) When the problem happens, it's fixed by restarting the modem it seems

    So unless the suggestion is to setup my PC NIC with the routers WAN MAC, connect it to the hub, get it running OK.. leave my PC on with wireshark trace going on overnight, and then see what's happened in the morning?

    Although as the other poster said if the issue is the modem talking to CMTS then it may be best to just get an engineer around as ultimately they may be able to just test everything live.

  • legacy1's avatar
    legacy1
    Alessandro Volta
    2 years ago

    Yes you could do that with this filter

    port 68 or port 67 or arp

    It could be that VM are doing work and clear the DHCP table same goes for modems 10. which maybe why you need to reboot the hub which would mean your connection has its lease as good and not need to redo DHCP but unpluging replug the Ethernet should trigger the DHCP client to start over so try that with PC if you get not internet.