Odd issue with superhub 3, modem only mode, network switches and powerlines

[meadwak]

So for years I have had my VM superhub 3 in modem only mode, and use my Asus RT-AX88U for DHCP and Wifi etc.Connected to the Asus router I have a couple of Netgear GS308 switches, and everything plugged into them, via Wifi, or directly plugged into Asus router. Internet and download speeds all work fine.

Recently (sorry for long description) noticed a few devices no longer connected to network, noticeably a TP-link powerlink (was being used to boost Wifi into sons bedroom). This plugged into one of the Netgear switches, and appears to refuse to pickup a IP address from the DHCP server, instead using a different range (in the 192.168.0.x range). Tried different cables and trying different ports on the same switch and the other network switch, and still it would not pick up a valid IP address (the powerlines worked, and I could connect to its Wifi, currently using a different Wifi name to rest of the house) but it (and any devices connected to it) had no internet connection. The only thing that worked was plugging the powerline directly into back of Asus router, which was not practical as it sits on a shelf above the Kitchen door (kinda centre of house) whilst the switches and Superhub are under the stairs. I tried using the powerline in dynamic mode (i.e using the Asus DHCP) and manual mode setting a IP address that could be set by the DHCP server, and set a IP rule in the Asus router to always give the device the same IP address)

I thought it was maybe a problem with the SuperHub modem mode somehow (i.e the superhub not quite being in modem only mode properly and maybe somehow using its own DHCP server). So I followed the guides on this site to put it back into router mode (with Asus router unplugged), followed the 4 steps to put back into modem only mode, rebooted it, powered up the Asus router, let it sort itself out and then plug that into the SH. Problem still persisted. Anothr issue is that before and after the reset I can no longer access the suberhub using the modem only mode IP address (192.168.100.1). I could access the superhub whilst it was in router mode just fine though. No idea how long that's going on for, but it makes me think the hub is somehow interfering with my network, although I have no idea how?

Any thoughts on why hub can't be accessed in modem only mode, and why certain devices refuse to pickup up a valid IP address from the DHCP server? (DHCP uses 192.168.1.x range). As a further test, I tried using another network cable on our Xbox One which usually connects via Wifi fine, and it also appears to be doing same thing as the powerline, and which is also plugged into the switch with a long cable under the floor boards. A DVD player, and a TV upstairs also do same thing - all plugged into one of the switches, and usually use Wifi, which is why I have not noticed before.

Searching online I can various instances of bad cable's, and dogey switches (one id new from last year), but can't find examples of certain devices refusing to connect regardless of what switch port they use!

Thanks in advance for any help ;-),

meadwak

[Roger_Gooner]

With hub in modem mode connect a laptop or similar and see if you get broadband (and if so what are the speeds).

[legacy1]

unplug all powerlines reboot devices and check things are stable

[BillBudd]

I recall reading somewhere that the IP address 192.168.100.1 is not actually the IP address of the router in modem mode.  It was the same problem.  So there might be something else on your network with that address.  Sorry, bit of a wooly description.  Hopefully someone with better knowledge will pitch in for you.

[Tudor]

Looks to me the the Hub3, it’s not a SuperHub, has reverted to router mode and you have two networks on the same wires. Best option is to unplug your own router and set up modem mode from scratch after doing a full 60 second pin-hole reset of the Hub3 (do not power off the hub as VM say, it will reboot itself). When back in modem mode follow these instructions: 

How to put a VM hub into modem mode:

1) Access your hub on 192.168.0.1, sign on and put it into modem mode. On the Hub3 the bottom LED will change to magenta, on a Hub4 the LED band will be green, on a Hub5 the LED will be green. Best done from a wired connection.

2) Turn off the hub and disconnect any Ethernet cables

3) Fully initialise your own router or mesh master unit and make sure the WAN port is set to DHCP (for some routers or mesh this may have to be done in router mode before entering modem mode)

4) Connect your router or mesh master unit to the VM hub with an Ethernet cable, Cat5e or Cat6, any higher specification is a waste of money. On a Hub5 use port 4.

5) Turn on the VM hub.

6) You should now be able to access the internet and the hub will now be on 192.168.100.1

Note1: this only needs doing once for each new router or when VM changes your WAN IP address.

Note2: If you have a Hub4 and your own router is NOT 192.168.0.1 then it’s possible that you can still access the VM hub on 192.168.0.1

[meadwak]

Hi all, thanks for responses so far..

Powerline units have been unplugged for last week (they had no internet anyway), and I still can't access hub interface whilst in modem only mode!

I have not read anything suggesting ip address for modem only mode is anything but 192.168.100.1, but will take another look to be sure (and powerlines used a different IP range as well, when they were plugged in!)

I think I said 4 steps in my original post, but the 6 steps plus hub reset that Tudor suggested were exactly the steps I followed (twice in fact).

Will check I can use a laptop directly connected via ethernet to hub in modem only mode, but I'd assume it will work as Asus router has internet when it's plugged into it, and at speeds I was expecting!

[Roger_Gooner]

You have to connect laptop directly to hub to check it out, why would you do it any other way.

[meadwak]

I've always used WiFi to connect to the hub, in router or modem only mode (not including it being plugged into Asus router of course), and as hub is under the stairs, didn't immediately occur to use ethernet to laptop. Need to do it in evenings after everyone had gone to bed, so will try tonight.

[Adduxi]

Yes, as noted by @Roger_Gooner  I would always use a laptop with a wired connection when working on the Hub.  There are too many things that can go amiss if using Wifi.

Note when you connect to the Hub in modem mode with a laptop/PC with a cable, this must be the only cable connected.  Also when the Hub gives out the WAN IP to the laptop, you will need to power off the Hub for a while to allow the laptop's MAC address lapse.  If you don't, you may have some issues with getting your Router connected. 

[meadwak]

So plugged laptop into hub3 whilst in modem mode, and after a reboot, and setting dns servers to googles (on the laptop), I had a working internet connection on laptop.

Visiting 192.168.100.1 I was now able to access the hub interface. It said it was in modem mode, but followed instructions above (60s pin reset etc), placed it back in router mode, and then back to modem mode.

Laptop (now on WiFi to Asus router), could still access hub interface on 192.168.100.1.

Oddly my phone, on same WiFi could not access the hub.

Tried powerlines again, and still same problem, appearing to ignore the DHCP connection from the Asus router.

So currently stumped! 🤔