Cable Modem or Router or ISP

My sister has an interesting situation. She called me yesterday and told me that there is no internet at her house. So when I checked the cable modem and router, the router could not connect to the cable modem. So this is what I did for both, trying to pinpoint the issue.

Cable Modem:
I contacted the ISP and asked them to reboot the Cable Modem. They were able to do it.
I was able to connect a laptop directly to the Cable Modem and got to the internet.

Router:
I took it to my house and connected it to my Cable Modem (same exact model). It took seconds to connect and when it did, everything worked, including the WIFI.

I went back to my sister's house and plugged her Router back into her Cable Modem. Again, it cycle and could not connect to the Cable Modem. So today, she bought a new Cable Modem and still, the Router cannot connect to it. After 10 minutes of cycling, it finally will connect but there is no WIFI. If we plug an ethernet cable from it to the laptop, we do get internet.

Is this an ISP thing?

Thread moved to proper forum.

You'll get better and faster help in this forum.

I doubt it is an ISP issue if you can connect directly to the modem.

What are the make/model of the modem and router?

Quote:

---

Again, it cycle and could not connect to the Cable Modem.

---

So you're checking the connection from the router's config page?

Connecting to the modern is very slow.sporadically populating the webpage.

Both are tp link and router is AC3200.

Yes, checking from router login page. I have reset and restored a backup bin.

Again, router works fine at my home, not my sister's home.

We need the model number of the Cable Modem also so we can see what options it may or may not have.

If the router works on your home modem, you can view and print or write down both the Modem and Router settings that are being used, including any IP addresses, subnet masks, etc. Then, you can compare those with the modem settings on the modem where the router does not work properly. There may be an IP address / subnet issue, or some other setting that needs to be adjusted.

Is this the router in question?

https://www.tp-link.com/us/home-netw.../archer-c3200/

Sorry for the incompletely information. I will supply to night when I get home. Yes that is the router

Make sure that BOTH cable modems are the same model number / firmware revision. There should be a sticker somewhere, and it should be shown in the configuration pages also.

Like jdc2000 said, we need the exact make/model so that we know what we are working with.

I'm guessing you tried different ethernet cables also?

Definitely check the firmware version on both the modem and router. Modems are usually updated by the ISP. Some routers have auto-updates.

It is weird, everything is back on now. The router was unplugged for 10 hours and my sister just plugged back in and Wi-Fi is working now.


I will update more tonight.

So here is an update. It has been sporadic. We worked with the ISP and we tried both cable modems (the new (Netgear) and the old (TP Link)). The router is able to connect for about 2 minutes and we would get internet and wifi. Then it drops and it doesn't work for 15+ minutes before we can use it again for about 2 minutes.

Here are the items:

Cable Modem: https://www.tp-link.com/us/home-netw...outer/tc-7620/
Router: https://www.tp-link.com/us/home-netw.../archer-c3200/

The new Cable Modem is a Netgear which I did not get the model information from my sister.

Did you try a different coax cable? Is there another coax wall jack you could try?

Quote:

---

The router is able to connect for about 2 minutes and we would get internet and wifi.

---

Are you sure that the router is losing connection to the modem? Even if the internet connection is dropping, the router could still be connected to the modem. Can you still connect to the modem config page? By default, it would be 192.168.100.1

Yes, I tried a different location for the coax cable as well as a different Ethernet cable between the router and modem.

I don't know if the router is losing connection from the modem but I do know that it works only for two minutes and then disconnect and then works again 5 minutes later. When it is connected, yes, I can navigate the 192.168.0.1 page but it is very slow at my sister's house. If I take the router home and connect to my modem, then it is normal, not slow.

I feel as if ISP lose connection every 5 minutes right? But then I realized looking at the Cable Modem lights, it is still lit correctly so it probably not the ISP or the Cable Modem. It is the Router losing connection to the Cable Modem. But then again, it could be the ISP because for both Cable Modem, if I connect the Ethernet cable directly from the Cable Modem to the laptop, it is still slow.

It can't be the Cable Modem because we bought a new one yesterday. So it has to be either the ISP dropping signals or the router. I have reset the router. What else should i be looking for in the router? JDC mentioned something about IP addresses, subnet masks.

The weird thing is that it has been working fine for years and all the sudden a few days ago, we lost connection.

192.168.0.1 is the ROUTER config page. I said to connect to the MODEM config page at 192.168.100.1.

Did you test your sister's modem with your router? Are both routers the same model?

If the connection is slow when you connect directly to the modem, then it could be an ISP problem. You might need to have a tech come out to the house if phone support can't find any issues.

Hi Mr. MidKnyte,

So here is an update. Everything is back up and normal when my sister bought a new router. It turned out to be the router which is weird since her router works at my house, but not at her house. The router was reset, many times over, and still was not able to connect to her cable modem.

This is a first because I have never seen a router go out. Cable Modem? Yes, have seen those many times but never a router.

Thanks for the update. That's weird about the router. Did you try updating the firmware or even going back one version? Anyway, glad you got it sorted out