The default gateway is not available/Possible DNS issue

I have been having this problem for a while now. Any time I connect my laptop directly to my modem via Ethernet I keep losing connection to the internet briefly. When I try to troubleshoot the issue it keeps "fixing" the default gate not available issue but the issue never actually gets fixed. When I ping out I get random spikes of ping > 500ms and timed outs and also "destination host is unreachable" messages. I feel like I have tried everything: updated my drivers, ipconfig commands, dims restore health command, turning it on and off again, and nothing has seemed to work.

Now this only happens with my modem. I can connect with my router via Ethernet just fine. All I have are "DNS may not be available" issues once in a blue moon. My modem is a Motorola Surfboard SB6180 and my wireless router is a Netgear N600.

I would be extremely thankful for any help. Here is my ipconfig /all as well.

First off, your default gateway is an IP address, so DNS isn't involved at all. Typically the gateway is where the DHCP server is, which provides DNS server info to the client.

What the most likely problem is, would be that your router uses a different subnet. For example, DLink routers tend to use 192.168.0.xxx, and Linksys routers have traditionally used 192.168.1.xxx. When you are connected via your router, the router is your default gateway and the IP address will look similar to the above. When you're connected directly to the cable modem, you're going to be using whatever the gateway for your cable provider is.

Your DNS issue is likely due to virtually every company that makes routers failing to take the time to sanitize certain settings given the constraints of the embedded platform, not to mention stripping the hardware back to basically the bare minimum needed to run the basic services, but then loading down the software with all kinds of other features. I would check the DD-WRT site and see if your specific model router is supported. If so, dump the official firmware, which is garbage pretty much universally.

Thanks for the advice! Unfortunately, my router is not supported by DD-WRT so that is a no go. That said, the dns issue with my router is pretty minor compared to the gateway issue with my modem. I can't stay connected with my modem for more than a few seconds without dropping packets while pinging out.

Also, I don't know if this will help or not but here is my ipconfig /all when I am connected to my router.


View attachment 53243

NotNobodyNever said:

Thanks for the advice! Unfortunately, my router is not supported by DD-WRT so that is a no go. That said, the dns issue with my router is pretty minor compared to the gateway issue with my modem. I can't stay connected with my modem for more than a few seconds without dropping packets while pinging out.

Click to expand...

Every time you switch between the router or the modem you'll likely need to manually switch between the two settings. So pick one setup or the other or be prepared to spend a lot of time swapping settings. For that matter, why are you frequently switching between directly connected to the modem and then through a router?

I usually don't. It was just something I noticed after I called my ISP when I was having trouble with my internet. Now anytime I have trouble with my internet I can't call them because they will just dismiss it as a hardware issue on my side. Nothing super major but can be annoying....