DNS Error while using 1 x Wi-Fi LAN and 1 x Ethernet LAN similtaneously

[dimpysync]

Hi,

I could use some focused help as trawling through other threads hasn't solved my problem.

- The problem: "DNS_PROBE_FINISHED_BAD_CONFIG" error message occurs and stops internet browsing.

- I'm using a single PC with multiple simultaneous LAN connections (1 x Wi-Fi and 1 x Ethernet).

- I physically have two routers doing this, one for the Wi-Fi and one for the Ethernet connections.

- Only the Wi-Fi connection has internet access, the Ethernet connection is an isolated home network for file transfer and media playing.

The problem may take a short while to manifest but in the end it always arises and I have to end up physically disconnecting the Ethernet cable in order to gain internet access again. My feeling is that simultaneously using both connections eventually causes some sort of IP/DNS interference between the routers.

Already tried:

- Changing Ethernet LAN interface metric to 500, Wi-Fi LAN interface metric to 300

- Changing Ethernet LAN IP to 192.168.1.1, Wi-Fi LAN IP to 192.168.0.1

- Using a different router as a substitute but the same issue occurred

Thanks in advance for any help you can provide.

P

 

[McHenryB]

Check in your routing table that the default gateway is the wireless router.

I'd be more specific but you don't say what operating system you are using. The defined routes should ensure that the wired connection is only used for the LAN and nothing else.

 

[tigerg]

Huh?

How is your network configured. If your wired router is not connected to the network in anyway, you can disregard it. Unless you have it plugged into the wireless router, in which case, it is probably not isolated.

 

[McHenryB]

That's a good point. The wired router is totally redundant; you just need a switch for the LAN.

But you still need to ensure that no gateway is assigned to the wired connection. That way it will only be used for connections to other computers on the same network; all other traffic will go via the default gateway for the wireless connection (your - should be - one and only router).

 

[dimpysync]

Hi, thanks for the interest.

I'm using Windows 8.1 Pro

The wired router basically connects the PC to the NAS, hence its a separate isolate network to the wireless one.

Thanks,

P

 

[tigerg]

Are the wireless router and the wired router connected to each other in anyway? I am trying to understand why you mentioned this if it really was completely isolated.

 

[dimpysync]

Are the wireless router and the wired router connected to each other in anyway? I am trying to understand why you mentioned this if it really was completely isolated.

No connections between them. The only shared link is the PC, while it is on.

 

[tigerg]

So the PC has an Ethernet cable to the wired router and then a second ethernet cable (or wireless connection) to the wireless router?

Which computer is giving the DNS error? The PC?

 

[McHenryB]

If all the wired router is connected to then just use a cable; no switch or router necessary.

Configure the wireless interface as normal.
Configure the wired interface so that it has an IP address on a different network to the wireless one; give the NAS another address on that network. The "Default Gateway" and "DNS Server" entries should both be blank (or all zeros) for the wired connection.

For example, if the wireless network is on the network 192.168.0.0 then set the wired connection settings as:

IP Address: 192.168.1.1
NetMask: 255.255.255.0
DNS Server: 0.0.0.0
Default Gateway: 0.0.0.0

Use the same settings (but with IP Address: 192.168.1.2) on the NAS. To make life easier you can make an entry in the hosts file on your computer for the NAS.

 

[dimpysync]

That's a good point. The wired router is totally redundant; you just need a switch for the LAN.

But you still need to ensure that no gateway is assigned to the wired connection. That way it will only be used for connections to other computers on the same network; all other traffic will go via the default gateway for the wireless connection (your - should be - one and only router).

That sounds like a good route to explore. Just to mention though, I had the wired router spare and didn't want to buy a switch if I could avoid it, which I think should be possible as I think I'm 95% of the way to the solution. In future, I plan to connect more PC's to the wired network.

As for the route table, how can i de-assign a gateway via the wired router?

Thanks

 

[McHenryB]

When you want to use more PCs on the LAN you can certainly use the router as a switch. Just make sure that it is not set to provide DHCP addresses and use static addresses for the devices on the LAN (you could do otherwise, but this is easiest). Unless you need a lot of devices on the LAN it will be easier to just use the hosts files on the computers rather than bothering with DNS for name resolution.

 

[dimpysync]

So the PC has an Ethernet cable to the wired router and then a second ethernet cable (or wireless connection) to the wireless router?

Which computer is giving the DNS error? The PC?

To answer your questions, there is a single PC with two connections. One non-physical wireless connection to the Wi-Fi router, and one physical Ethernet connection to the Ethernet router. There isn't a second cable.

Thanks

 

[dimpysync]

When you want to use more PCs on the LAN you can certainly use the router as a switch. Just make sure that it is not set to provide DHCP addresses and use static addresses for the devices on the LAN (you could do otherwise, but this is easiest). Unless you need a lot of devices on the LAN it will be easier to just use the hosts files on the computers rather than bothering with DNS for name resolution.

I've tried the IP's as you suggested but the error is still occurring. I'm unable to covert to static IP's on the wired LAN as that seems to be a WAN only option. Could you give an example of the text that should be inserted into the hostfile in my situation?

 

[bill001g]

Life will be much easier if you can set your ip static. It is done in the network setting for the ethernet on your pc not on the routers.

The key here is to leave the default gateway blank and to leave the DNS fields blank.

If you really can't do that you can delete this information from the data the dhcp is sending you.

First open a CMD window in admin mode.

The do
ROUTE PRINT
Find the 0.0.0.0 entry that points to ethernet gateway and use the ROUTE DELETE command to delete it.

To get rid of the DNS you need to use the

NETSH INTERFACE IP

There is a show and delete options on this command also.


.....I would recommend you use the static ip in the networks setting rather than mess with the commands. You can make quite a mess that will require a reboot if you do it wrong.