Multiple dns-related problems

[Demosthenest]

I have 300mbps down and 30 up. It's very fast but lately there are random times when it won't work.
There are 4 smartphones, smart tv, 1 desktop and up to 4 laptops connected to it. It seems that when there are more devices connected the issues are more likely to happen.
My router is a Comtrend 5813
I start getting errrors with name resolution in multiple computers which basically renders the wifi and ethernet unusable. I usually have to restart it, which sometimes solves the problem.
Also, when I load my pc, ethernet is on limited connectivity, I have to right click "detect problems" and then it fixes it. Error message says ethernet did not have a valid IP adress.

 

[techgeek]

Are you using your ISP provided DNS servers? You could manually set them for something like Googles (8.8.8.8 & 8.8.4.4) or OpenDNS (208.67.222.222 & 208.67.220.220) and see if that helps. If you have access to the administration of your router, you can specify these in the DNS settings. If you don't (because your ISP has locked you out), you can enter then in each device connected to your network which will bypass the ISP DNS servers.

However it seems odd that you get Ethernet did not have a valid IP address. Have you checked to see what you IP address is when this occurs?

 

[Demosthenest]

I use ISP DNS, yes. I have tried using those dns you recommended before and they sometimes fix the issue. I'm currently using the google one. I only use them on the IPV4 tab, on ethernet propierties, however, I've never changed my router's DNS (just checked and it's not locked). I'm kind of a noob when it comes to connectivity.

I'm not really sure how to check it since I don't have internet acces until I "fix" the issue with the windows network diagnostic.

 

[techgeek]

Can you reach your router's administration page when you're disconnected from the internet? If not this points to something more than DNS problems. DNS should only affect external traffic, you should still have LAN access which would includes access to your routers administration page.

As for checking your IP address, you should be able to do this via the Command Prompt window, type ipconfig. This will dump all the basic information for all your network devices on the computer (wifi, ethernet, etc). Check your IPV4 address and make sure it's in the valid range (dependent on what the router assigns) usually something like 192.168.xxx.xxx.

As for manually specifying the DNS servers in router settings, this just simplifies using alternate DNS's. The way you are doing it now has to be done for each device. Doing it in the router will work for all devices without changing anything on the connected devices.

Though I've seen issues with ISP's DNS servers (particularly with satellite connections), they usually aren't a permanent issue. They can be slow though, that's why the alternatives are better. I use OpenDNS because I'm a father and I can limit access to "certain" material that way. However if my kids caught on to networking, they could bypass it locally at their computer. Luckily none of them have much interest in learning about networking, so I've been lucky so far.

 

[Demosthenest]

I've booted up a couple times and the IP issue hasn't happened. I'll leave this open for a couple days and tell you if it does or the DNS issues persist with the router configured with google's.

 

[techgeek]

Sounds good.

 

[Demosthenest]

Ok so I checked ipconfig next time it happened and the difference was that before fixing the problem with windows network diagnostics, the "connection getaway" said 0.0.0.0 and then under that the normal one. With the problem fixed, there was only the normal one (192...)

 

[techgeek]

If you are getting 0.0.0.0 when the problem occurs, and all your devices have lost their internet connection, then your router is dropping out. This could be hardware related or firmware. Is the Comtrend WAP-5813n your own? Or was is supplied to you by your ISP?

If it's yours, check to see if there is a newer firmware available. If not, I'm thinking you may have to replace your router. If it was supplied by your ISP, you maybe able to get them to replace it. I'm assuming from the little I've found about it, it's got to be about 6 years old. According to Comtrends website, it's a draft N router. 802.11n didn't get ratified until October 2009 with products coming out shortly afterwards. So that router is getting up there.

So first, see if there is a newer firmware and if there is flash it to the router. If that fixes the problem, then you're good. If there isn't a newer firmware, or there is, but it doesn't fix your problem, then you may need to look at replacing it.

Once thing you could check, is your router in a well ventilated area? I've heard of routers that are in confined spaces overheating and causing issues such as this.