[SOLVED] Modem disconnects are causing router to lose DNS

[eszed556]

Hi. Recently there was a service outage at Cogeco (ISP in Canada). Since then my router (TP Link Archer 10) has been disconnecting every few minutes. However, some WiFi and wired services work even though the router shows disconnected internet.

The ISP device is a modem with a built-in router. Since I prefer to use a 3rd party router, I have put the ISP's device in bridge mode to disable it's WiFi. Everything was working well till the outage.

Initially a hard reboot of the modem fixed the problem. But today the ISP performed a manual reset and the problem is back. I have tried to reset my router but that didn't help.

My router shows Internet is disconnected. I can ping my router w/o errors and the service lights on my modem are green (as they should be).

I suspect there is a connection issue b/w the router and modem. Can I resolve this myself?

 

[Ralston18]

Two thoughts:

1)

"I have put the ISP's device in bridge mode to disable it's WiFi. "

You may need to do that again. And perhaps a bit more.

2)

" I have tried to reset my router but that didn't help. "

By "your router" you mean the Archer 10 - correct?

If the ISP reset their router it may be back to a default configuration that re-enabled its' router functions. And you now have two active routers.

Only one router should be enabled.

Disable the ISP router's DHCP IP and let the Archer 10 handle all the network DHCP IP addressing.

 

[eszed556]

Thanks.

1) It seems I am unable to access my ISP modem UI since its been put in bridge mode. I will need to create a ticket with them. I am also not sure if their bridge mode disables WiFi broadcasting and/or DHCP server. However, since I've had it in bridge mode 4 weeks ago, I have been experiencing zero issues.

2) Yes, by router I meant the A10

I have also rebooted my A10 and the modem, it did not help. Sporadic connectivity. However, certain services like Netflix (wired TV) are running w/o interruption.

Assuming the modem is still in bridge modem (which it is, I can't find the wireless network) would it help if I disable DHCP on my router?

Is there any risk of getting locked out of the A10 if I disable DHCP?

 

[Ralston18]

Multiple scenarios:

1) Both modem and router are acting as a router.

2) Neither modem or router is acting as a router.

3) Modem is the "router" and the router is no.

4) Modem is not the router and the router is acting as a router.

I would not expect that you would get locked out per se but you certainly could cause the wired TV to lose network connectivity due to not having a viable DHCP IP address from either modem or the A10.

Or if the TV has been configured with a static IP then resetting either modem or router to default values would/could likewise may the TV unable to connect. Same for other network devices.

Other issues: Your ISP's modem and TP-Link Router both may want to be the "one-ring". So you may need to go online via a web interface to make configuration changes. And it may be a bit tedious to get that all sorted out.

You can regain control of the situation by sketching out your network. The sketch does not need to be a "work of art" Just simple and clear.

Here is a line diagram that represents typical connectivity. (You can easily find more elaborate and detailed network diagrams on line.)

ISP ---- coax, fiber, DSL, cable ----> ISP modem ----- Ethernet cable ---->[WAN port] Archer 10 Router [LAN ports] ---Ethernet to wired devices ---> and ~~~ wireless ~~~> Wireless devices.

The ISP's modem (if a combo modem/router) usually has its router functions disabled. All router functions are then handed by the Archer 10 mainly providing DHCP IP addresses to requesting devices.

Archer 10 User Manual link

https://www.manualslib.com/manual/1704521/Tp-Link-Archer-Ax10.html?page=12#manual

See physically numbered Page 8 regarding connectivity. [Do verify that I found the correct User Manual.]

Then use "ipconfig /all" to look at the network adapter configuration settings for each of the network computers or directly look at the network configurations setting for other devices. Wired or wireless.

On your diagram showing each computer or device; note the IP address of the device's DHCP server, the subnet mask, and the assigned DHCP IP address. Any static IP addresses that are in use should be noted if you assigned a static IP.

What I would expect (based on the A10 User Manual) is that all network devices will be looking for a DHCP IP address via the A10 router's Default Gateway IP address of 192.168.0.1 (subnet mask 255.255.255.0) per Page 61 of the A10 UM. Default DHCP IP address range being 192.168.0.100 - 249. Basis that none of that has been changed since the last reset (if any).

Focus on getting the big picture and then we can all work on getting it sorted out to work as it should.

 

[eszed556]

Excuse the delay.

I have not experienced any DNS issues since 10 days now. It turned out that the ISP was misrepresenting and pointed fingers at 3rd party routers - no surprise there. I asked around in my neighborhood and checked various forums and realized there were 100s others with the same issue as mine. The DNS issues were at the ISP's end.

Except for a few modem resets and reboots after my post, nothing in my network has changed. In fact, the ISP assumed their modem was faulty and sent me a replacement 2 weeks ago. This too is in bridge mode and I have been running this since 4 days now w/o issues.

What I would expect (based on the A10 User Manual) is that all network devices will be looking for a DHCP IP address via the A10 router's Default Gateway IP address of 192.168.0.1 (subnet mask 255.255.255.0) per Page 61 of the A10 UM. Default DHCP IP address range being 192.168.0.100 - 249. Basis that none of that has been changed since the last reset (if any).

The above is true and confirmed by running the ipconfig command. I only changed the A10's access page address as it was in conflict with the ISP's modem. It shows the A10 new access page IP address as the Default Gateway and subnet mask as 255.255.255.0. Your input is valued as it forced me learn and connect the dots.