Asus RT-AX86U + Virgin Media Hub 3 - "Your ISP’s DHCP Does Not Function Properly"

[HainesyP]

The RT-AX86U is an excellent router (especially for the security conscious) and has significantly improved the speed and stability of my home Wi-Fi network.

However, I wasted many hours trying to get the new router to work with the Hub 3 reconfigured to modem mode, with the Router reporting a "Your ISP’s DHCP Does Not Function Properly" message.

I searched lots of forums, trying out various suggestions (none of which worked) and got to the point where I was about to box-up and return the Router (assuming it might just be incompatible with the Hub 3).

However, as one final thing to try, I decided to reset reset the Virgin Media Hub 3 to factory defaults (by pushing a pen into the reset button at the back for 10 seconds), then immediately setting it to Modem mode before configuring it or connecting any devices. I also reset the Router, connected them together and hey presto, it all just worked.

I suspect the Hub 3 has issues with reconfiguration. The settings might look as though they should work, but the device doesn't appear to have properly reconfigured itself. So don't waste your time. I recommend you just backup the current configuration of the Hub 3, reset the device to factory defaults (using the reset button), and set it to Modem mode before doing anything else. Then you should just be able to connect and power-on the Router.

[lotharmat]

These issues mainly occur due to not following a set process to initialise everything:

1. Navigate to 192.168.0.1
2. Log in to the Hub
3. Go to 'Modem mode' (on the left) and put the hub into modem mode
4. Wait until the bottom light on the Hub turns magenta / red (HUB 3) (can take about 5 minutes)
5. Turn off the Hub
6. Power on and set up your new router as per the manufacturers instructions
7. Plug an ethernet cable (usually supplied with the new router) from port 1 on the Hub into the WAN (usually blue) socket on the new Router
8. Power on the Hub and wait about 5-10 minutes until it stabilises - You should have internet!

Step 5 is the key one - you need to have your router configured with the hub off.

[Adduxi]

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@HainesyP wrote:

<snip>  I suspect the Hub 3 has issues with reconfiguration. The settings might look as though they should work, but the device doesn't appear to have properly reconfigured itself. So don't waste your time. I recommend you just backup the current configuration of the Hub 3, reset the device to factory defaults (using the reset button), and set it to Modem mode before doing anything else. Then you should just be able to connect and power-on the Router.

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There are hundreds of threads on this Forum of how to connect in Modem mode.  The main issue is not the Hub 3, but the correct sequence.  Yes, the Hub 3 does not do hot swap, but holds on to the last MAC address.  So you need, as you discovered to power off the Hub 3 when it's in Modem mode. Then setup the Asus in DHCP mode, connect the WAN of the Asus to the Hub.  Only then power on the Hub.  This will allow the Hub to negotiate a DHCP WAN lease with the Asus.  Note - This only needs to be done in this sequence once, unless you replace the Asus.

[HainesyP]

I did all that (including switching The Hub 3 of for 10+ minutes) several times, but it made no difference. I spent the better part of 4+ hours on this and had almost given up.

However, i had a similar issue with the same Hub 3 last year when trying to configure port-forwarding. Configuration looked as though it should work, but despite numerous configure/power off cycles, it just wouldn’t forward the ports (I’ve been a software developer for 20 odd years and am now a cyber security specialist so I’m far from a newbie at this sort of thing). Anyway, even Virgin Media tech support helpline couldn’t help fix it. Again as a last resort, I factory reset the Hub 3, configured it from scratch, and it all just worked. That’s why I’m concluding that my hub 3 has issues with reconfiguration.

[Adduxi]

Yes, port configuration is a known "feature" in the firmware.  From memory the numbers had to be input in ascending order to work? 

Thankfully, I've never used any of the Hubs from VM in anything other than Modem mode. It saves a lot of grey hairs and sanity running you own IT kit behind the Modem  🙂

[HainesyP]

Agreed,

I was somewhat sceptical as to whether a separate router would make that much difference in terms of performance. My main motivation was security to be honest (the AX86U has Intrusion Detection and Prevention and VPN server functionality). But I have to say I’m pleasantly surprised at the Wi-Fi range and performance increase, and the event logging and alerting features are pretty good too.

I don’t intend to back to Router mode…

[Adduxi]

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@HainesyP wrote:

Agreed,

I was somewhat sceptical as to whether a separate router would make that much difference in terms of performance. My main motivation was security to be honest (the AX86U has Intrusion Detection and Prevention and VPN server functionality). But I have to say I’m pleasantly surprised at the Wi-Fi range and performance increase, and the event logging and alerting features are pretty good too.

I don’t intend to back to Router mode…

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I use a an older Draytek Vigor Dual WAN 2860 with similar specs, with PoE access points at the moment.  At some point, I'll upgrade to a new Vigor as my old one only has a WAN throughput of 300 Mb.  The Dual WAN aspect works a treat though, with VM and BT running concurrently load balanced.

[lotharmat]

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@HainesyP wrote:

I don’t intend to back to Router mode…

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Ditto!!

[Guybrush85]

The AX86u is a cracking bit of kit! I believe even in the manufacturer firmware you can now enable DoT, but I chucked mine onto Merlin in about the first 5 minutes of starting it up.

If/when you'll be pleased to know the hub 5 with it's 2.5Gbit port can utilise the 2.5Gbit on the AX86u for WAN connectivity should you ever move to Gig 1 (or future products yet to come).