LAN stopped working - Virgin TC7200 with Asus RT-AC66U

FrankGrimes

I've got a Virgin Media Technicolor TC7200 router/cable modem (don't believe I ever switched the mode on it, think it's still in default mode) running firmware version STD6.01.12. Ethernet cable connects this to my Asus RT-AC66U running stock firmware (latest version) which I use to configure my ethernet and wireless network.

No issues but then couple of weeks back, just before going on holidays, ethernet stopped working. Plugging devices directly in to router, or even into the TC7200 just to try it, does not work. Devices connected to RT-AC66U via ethernet can see each other, but no internet access. Wifi internet access remains unaffected.

Only change I can think of is I around the same time added my Horizon box to my network via ethernet so I could access it with the remote app. Have since disconnected it and done a hard reset (20secs on reset button, power still in) on TC7200 and done a reboot on RT-AC66U. No joy.

Asking here as I know there's a lot of knowledge on resolving Virgin issues and any time I have dealt with UPC/Virgin directly, it has been a very painful experience so I want to avoid going to them if possible.

I'm also about to add some wireless cameras to my network and need to set things up so I can access them remotely, guessing there'll be some router config to be done for that, so if there's an opportunity to do both that and fix above issue at same time, thought I'd mention it. Thanks.

degsie

You need to check that the TC7200 is serving as your primary DHCP server for both wireless and wired. Remove the asus from the setup, connect a laptop via wireless to the TC7200 and run 'ipconfig /all' from cmd prompt, then disable wireless and connect directly to the 7200 via ethernet and run same command. Compare results.

FrankGrimes

FrankGrimes wrote: »

Plugging devices directly in to router, or even into the TC7200 just to try it, does not work.

If you're getting nothing on the TC7200 directly then it sounds like a call to VM is needed.

FrankGrimes

Thanks folks. degsie, I ran IPCONFIG in several different scenarios. I've got a desktop and a Surface Pro, so had to use a USB ethernet adapter with the Surface.

Attached has IPCONFIG output for 3 scenarios: wireless to TC7200, ethernet to TC7200, ethernet to RT-AC66U (which is only in this scenario connected to TC7200 via ethernet).

Getting a strange scenario where if I plug the USB ethernet adapter into the RT-ACC6U via ethernet, I get internet connection. But if I plug same ethernet cable directly into the desktop it won't have internet connection.

I'm not an expert but from a glance the IP assignments seem to make sense: 192.168.0.12 and 192.168.0.13 with gateway 192.168.0.1 for the direct to TC7200 connections. 192.168.1.250 with gateway 192.168.1.1 for the connection to the RT-AC66U.

In TC7200 settings page, DHCP Server Enable is set to Enable with Starting Local Address 192.168.0.10. Given that I want the RT-AC66U to handle all IP address assignments within my network (I want the TC7200 to basically just pass the internet connection tot he Asus), should I leave this enabled?

I'm a bit baffled how the desktop still won't get internet connection but connecting the Surface via USB ethernet adapter to the Asus does give internet connection.

degsie

On the second ipconfig test you appear to be using a usb to ethernet adapter, which works? I'd suggest test again with the desktop only, so wired and wireless without the adapter. Introducing the usb adapter may confuse things.

FrankGrimes

Thanks again degsie. Attached file now contains outputs for 4 test scenarios all from the desktop - no USB ethernet adapter used here, though for the wireless connections I did use a USB wireless adapter as the desktop does not have integrated wireless.

Anything showing up as a potential issue/resolution here? I am at least getting an IP address in all scenarios.

On a related note, for the various gadgets I'm about to add to the network and wish to access remotely, is there any change I should make to enable this (e.g. specify Asus IP as DMZ for TC7200, change mode etc.) that'll make the remote access work? Might aswell do that at same time as fixing the LAN issue - know there's lengthy threads on this, if there's a staring place you could point me to that'd be much appreciated.

degsie

FrankGrimes wrote: »

Thanks again degsie. Attached file now contains outputs for 4 test scenarios all from the desktop - no USB ethernet adapter used here, though for the wireless connections I did use a USB wireless adapter as the desktop does not have integrated wireless.

Anything showing up as a potential issue/resolution here? I am at least getting an IP address in all scenarios.

On a related note, for the various gadgets I'm about to add to the network and wish to access remotely, is there any change I should make to enable this (e.g. specify Asus IP as DMZ for TC7200, change mode etc.) that'll make the remote access work? Might aswell do that at same time as fixing the LAN issue - know there's lengthy threads on this, if there's a staring place you could point me to that'd be much appreciated.

Your DNS server IP addresses are very different from wired to wireless. You should look there first.

FrankGrimes

Thanks degsie, that does seem to be the core of the issue. I've now tested it with several different configurations and just can't get it to not assign 192.18.0.1 and 192.18.0.2 as the DNS Servers when using ethernet.

When using wireless, it seems to pick up the DNS server IP addresses I specify. I specified first the Virgin IPs and then the Google DNS IPs (8.8.8.8 8.8.4.4) in the TC7200 admin page. Also tried entering 8.8.8.8 in the 'DNS and WINS Server Setting' on the Asus LAN page, not sure what WINS is so didn't enter anything there. Also tried with 'Connect to DNS Server automatically' on the Asus WAN page set to Yes (default) and No (and entered in 8.8.8.8 and 8.8.4.4 as the server addresses). This all led to changes in DNS for wireless, but still no change on ethernet.

As I'd then ran out of ideas, I googled the 198.18.0.1 DNS server address and got this page: https://support.ipvanish.com/customer/portal/articles/1968391-dns-leaks I installed IPVanish recently so it now seems likely this is adding some complication.

Just FYI - not sure if this is relevant: I have IPv6 set to Disabled on the Asus settings page, and on the TC7200 settings I don't get any setting saying IPv6 (not sure if there's a later version I should have).

Further searching showed this page where someone had their IPv4 settings for their ethernet adapter set to manual DNS server address. I don't recall changing that setting, but am guessing IPVanish did it during the install. Changed it back to Obtain DNS automatically, and it worked.

So now everything seems fine, I had written this post in stages as I worked through it, but thought best to share outcome in case anyone else encounters similar.

Thanks a lot degsie for the pointers. I'll now get cracking on setting up the remote access for my gadgets - as it seems like there's a mine of info out there on this topic (changing router mode etc.), if there is a handy thread I should use as my starting point please let me know!

degsie

Good to hear you are getting things sorted

With regard to a remote access you need to figure out port forwarding. portforward.com would be a good place to start.