Issues with Hub 5x in modem mode

[bryrant]

Hi all, I've had a bit of a hell of a time and hoping I can get some feedback and ideas on what exactly is going on with my Virgin Media Broadband.

My Initial Problem:
I work from home, and as part of that work I need to access services hosted on private IP addresses. This does not seem to be possible with the Hub 5x. I've helped colleagues with similar issues in the past, and the fix has always been to update the DNS servers to be used to 8.8.8.8/8.8.4.4. This fix does not work on the Hub 5x for some reason.
I'm not sure why, but it seems like something in the router is blocking any responses that return private IP addresses. I have run some Wireshark capture, and that seems to be what is happening; I nslookup public IP @ 8.8.8.8 I get a response happily, I nslookup private IP @ 8.8.8.8 I get no response at all.

In the 5x settings page at 192.168.0.1, I also tried a ping (error starting ping) and a traceroute which returned the following:

Host Host address Error code Retry times (ms)

perr-bng-1-sub.network.virginmedia.net

86.2.32.1

0

8

7

-

My Fix:
After some searching I found that I may be able to set the DNS servers manually by using a separate router, so I got a TP Link Archer AX12 to test this. So I went through quite a bit of struggle to get the 5x into modem mode, I set the DNS servers on the TP Link to 8.8.8.8/8.8.4.4 and when I connected to the internet through the TP Link network I could access my private IPs!

More Pain:
That worked for about two weeks fine (just until the cooling off period ended, sods law). Then things started going wrong. It feels like there's been a dozen different things happening, but I'm not really up to scratch on the hardware layers of networking so I may not be very helpful.

• Internet randomly drops daily, sometimes the TP Link loses connection to the 5x. Sometimes the 5x just seems to fully lose connection. This happens 2-5 times a day at random times.
  Usually this could be fixed by factory resetting the 5x and putting it back into modem mode.
• Over the weekend I tried just using the 5x without TP Link connected, but it still had issues and at one point was down for 24 hours, before miraculously coming back up by fiddling with some wires.
• This morning the TP Link network was not sending out internet, and the 5x was not doing anything. It was in white, whereas normally it is green for modem mode. Factory reset did not work at all, even holding it down for 60 seconds. For some mad reason I turned the 5x upside down at THAT seemed to do it, and it is now sending out the internet across the TP Link network and the VM network.

I've not tried anything else this morning, like setting it to modem mode in fear of not being able to work further this morning. 

Not sure if it matters, but both the hub and the TP Link are plugged into one outlet with an adapter, as the location of the Hub only has the one socket. Also it may have been random coincidence, but at least one of the times the internet dropped it was just after my partner returned and added another device to the network. We don't have a disgusting number of devices probably under a dozen, so I can't imagine this is the cause.

I'm happy to go and grab any logs that may be helpful if you can direct me to where I could find them.

In Summary
This has been long and rambling, but essentially what I want is a stable internet connection while being able to access my private IP addresses for work. Whether this is through the Hub 5x or the TP Link I am not fussy, I just want it to work.

Thanks in advance.

[jpeg1]

Firstly, modem mode on the Hub 5x is not officially supported and doesn't appear to be reliable. 

Secondly, what do you mean by "Not sure if it matters, but both the hub and the TP Link are plugged into one outlet with an adapter, as the location of the Hub only has the one socket."?   You cannot connect anything to the VM network except their Hub. 

[bryrant]

Sorry, should have been more clear. I'm talking about mains power. We have a single power socket, with an adaptor with two sockets to supply power to the TP Link and 5x Hub.

Regarding modem mode, I had seen stuff about it not really being supported and it's definitely tricky to get it working. But it is literally the only thing I've found to make it work. I guess if it isn't officially supported I'm out of luck?

Do you have any idea of a way around my private IP issues using the 5x Hub natively?

[Client62]

"plugged into one outlet with an adapter"  - read as use of a 13A mains double adaptor

[jpeg1]

I'm sure the mains supply will have no effect. 

There are many reports on modem mode here, and links to other places, but unless I've missed it there is no report of being reliable in the longer term particularly if the WAN IP changes.  If you haven't already done so I suggest you read up on all of them.

Certainly if modern mode is working properly you should have no problem using your own router.  I have used every VM Hub model up to the Hub 4, always in modem mode, without any issues at all. 

[bryrant]

Thanks for the advise on reading up, there was some very informative posts that had escaped my notice.

There were two things mentioned, both by you @Client62

• In this thread, you mention some VM DNS blocking internal IP addresses. I may have misunderstood what you've said there but it sounds similar top what I'm experiencing, even though that post seems to be concerning the Hub 5 not the 5X
• In this thread, you say that 'DNS Queries for some AWS hosts time out with both VM DNS & any Public DNS - blocking genuine websites'. The private IP addresses I am trying to access are in fact hosted in an AWS VPC. This sounds very much like what I'm experiencing.

I'm not sure if there's much help that could be given from the general feeling of all the other threads in this forum. But seeing as you commented on the thread already and seem to have some info on issues I am facing, I would be very grateful if you could give any advice. Even if it's VM has forsaken you and there is nothing to fix your issues, it would be good to know for sure.

[legacy1]

modem mode don't work router mode not that good welcome to the future of fibre!

[Client62]

Below is an nslookup via a Hub3 that has not been intercepted i.e. works normally :

>nslookup hp.com 8.8.8.8
Server: dns.google
Address: 8.8.8.8

Non-authoritative answer:
Name: hp.com
Addresses: 15.72.80.135
15.73.145.56

When performing : nslookup hp.com 8.8.8.8 via the Hub 5x, is the response from dns.google / 8.8.8.8
or from some other IP or DNS host  i.e. a DNS redirection / interception has occurred.

[bryrant]

Looks like I get near exactly the same as you on a nslookup for hp.com:
❯ nslookup hp.com 8.8.8.8
Server:        8.8.8.8
Address:    8.8.8.8#53

Non-authoritative answer:
Name:    hp.com
Address: 15.72.80.135
Name:    hp.com
Address: 15.73.145.56

So it doesn't seem like a redirection/interception has occurred, at least when nslookup-ing hp.com. But if I try to nslookup on a DNS name for something we host on an internal IP in our work VPC I get no response (I've substituted the exact DNS name & IP Addresses below, even though I doubt anything bad could be done with it I'd rather keep it off a public forum):
❯ nslookup <<INTERNAL DNS NAME>> 
;; connection timed out; no servers could be reached

If I try the above nslookup while connected to my phone hotspot or on the TP Link while 5x is in modem mode I get:
❯ nslookup <<INTERNAL DNS NAME>>  8.8.8.8
Server:        8.8.8.8
Address:    8.8.8.8#53

Non-authoritative answer:
Name:    <<INTERNAL DNS NAME>> 
Address: <<CORRECT IP ADDRESS 1>>
Name:    <<INTERNAL DNS NAME 2>> 
Address: <<CORRECT IP ADDRESS>>
Name:    <<INTERNAL DNS NAME>> 
Address: <<CORRECT IP ADDRESS 3>>

Also, if I do nslookup against the internal DNS name while connected to my hotspot, but tell it to use '194.168.4.100' which I understand to be the DNS Address used by Virgin Media, it will hang in exactly the same way as the 5x Hub.

So I reckon there is something going on in the 5x Hub while it is in router mode that refuses to return any private IP addresses.

I don't know if there's anything you can do with all that, but that's my working theory. I appreciate it's a bit messy.

[Client62]

If when using a mobile phone's hotspot the VM DNS 194.168.4.100 does not respond,
that would be very likely as VM's DNS 194.168.4.100 is not a Public DNS.