LAN doesn't have a valid IP config

[CptDavenport]

Hi guys I'm new to the forums

I've just bought a new computer, completed the build and also installed Windows and basic drivers, but then I've encoutered a problem.

I have the Z87X-OC motherboard from Gigabyte and installed LAN driver downloaded from the Gigabyte website then plugged in the LAN cable.

But I can't access the internet though I was able to connect to the homegroup with my Laptop and was able to see and copy files from the Laptop.

When I try to fix the problem with Windows it tells me my LAN connection doesn't have a valid IP config.

Can anyone help me fix the problem?

Many thanks in advance

[rustikles]

So, you're able to see other devices on the local network, but you don't have internet connectivity? Make sure everything is securely plugged in around your modem/router, and power cycle everything in order starting with your modem and ending with your computer. This is a utility that has some mini-fixes for common windows issues (it might help, might not). 

 

Also, try using the build-in windows network troubleshooting. Right click the network icon in the task bar, and select "troubleshoot problems."

[CptDavenport]

I've checked everything, my laptop and the new computer are plugged into the same router and I only have Internet on the laptop.

Also I have a wireless router also plugged into the Gigabit router and if I plug the LAN cable from the desktop into the wireless router then it has internet, plug it back into the gigabit router and the same thing as before, no internet...

[rustikles]

Let me make sure I understand correctly. Your network:

 

Modem---->Router#1---->Router#2

 

You plug a LAN cable into #1, it works.

You plug a cable into #2, it doesn't.

[rustikles]

I've checked everything, my laptop and the new computer are plugged into the same router and I only have Internet on the laptop.

Also I have a wireless router also plugged into the Gigabit router and if I plug the LAN cable from the desktop into the wireless router then it has internet, plug it back into the gigabit router and the same thing as before, no internet...

Another support ticket from MS with instructions on resetting your TCP/IP settings entirely. It might be a good thing to try as well.

[CptDavenport]

I've tried to do as told in the Microsoft support ticket but the problem is not solved, I'm trying the utility now...

My setup is:

Internet from the dorm ===> Router 1 (Gigabit router) ====> Router 2 (Wireless router)

My laptop is plugged into router 1 and when I try to plug the desktop into router 1 then I have no internet. Plugging the desktop into router 2 (the wireless router) helps, there I have internet.

[CptDavenport]

This is weird.

So far I've also tried out the utility with no luck either.

The autoconfig IPv4 is 169.254.57.6 with the subnet mask 255.255.0.0

The IP should be 172.20.... similar to that on my laptop I suppose

I tried to set the IP manually then it worked, but it was supposed to obtain the IP addresses automatically...

[rustikles]

I've tried to do as told in the Microsoft support ticket but the problem is not solved, I'm trying the utility now...

My setup is:

Internet from the dorm ===> Router 1 (Gigabit router) ====> Router 2 (Wireless router)

My laptop is plugged into router 1 and when I try to plug the desktop into router 1 then I have no internet. Plugging the desktop into router 2 (the wireless router) helps, there I have internet.

So, it's most likely not going to be a problem with your computer. Can you give me the models of your two routers? It may just be a case that you have router#1 set up as strictly a pass-through with disabled LAN connectivity or something. Unless you have a reason to, it's not best practice to have multiple routing devices set up behind each other like that. Can you not just use your wireless router by itself?

[rustikles]

This is weird.

So far I've also tried out the utility with no luck either.

The autoconfig IPv4 is 169.254.57.6 with the subnet mask 255.255.0.0

The IP should be 172.20.... similar to that on my laptop I suppose

I tried to set the IP manually then it worked, but it was supposed to obtain the IP addresses automatically...

Again, that sounds like you have the first router set up incorrectly for having devices connected. Is DHCP turned on for router #1? (let me know if you need help answering that)

[CptDavenport]

The Gigabit router is a TP-Link Router: TL-SG1008D

The Wireless router is a D-Link DIR-600

I bought the Gigabit router first as it was a good deal on eBay, then I need a wireless router for my smartphone and sometimes my laptop so I bought it later.

I had another computer before this one and it had no problem with the Gigabit router so now I really have no idea why it keeps handing out wrong IP...

[CptDavenport]

Again, that sounds like you have the first router set up incorrectly for having devices connected. Is DHCP turned on for router #1? (let me know if you need help answering that)

I'm not sure if it has DHCP enabled.

From my laptop when I go to details on LAN connection I can see DHCP enabled but I guess that is only on my laptop right?

From the desktop which now has manually configed IP I see DHCP not enabled.

How can I tell if the Gigabit router has DHCP enabled?

[rustikles]

I'm not sure if it has DHCP enabled.

From my laptop when I go to details on LAN connection I can see DHCP enabled but I guess that is only on my laptop right?

From the desktop which now has manually configed IP I see DHCP not enabled.

How can I tell if the Gigabit router has DHCP enabled?

Ok so what you were calling "router #1" is actually a switch, which is a different device. It simply turns one ethernet port into multiple. That means your IP address is being handed to you by whatever handles it beyond your dorm room. So, it could be a case that your dorm internet is set up to only allow one IP to be handed out automatically. By hooking up a device to your switch, both your wireless router and your switch-connected computer are requesting IPs. 

 

When your computer is behind your wireless router, only one IP (the router itself) needs to be assigned an external IP, and everything else is handled correctly. 

 

tl;dr : You need to plug everything into the wireless router or move the switch behind your wireless router.

[CptDavenport]

Googled about the Gigabit switch, it's a switch and not a router so it doesn't have DHCP I think.

But then what is the problem with the IP address and how to fix it?

[rustikles]

Googled about the Gigabit switch, it's a switch and not a router so it doesn't have DHCP I think.

But then what is the problem with the IP address and how to fix it?

^See above, and feel free to mark the thread as resolved if you don't have any other questions!

[CptDavenport]

Ok so what you were calling "router #1" is actually a switch, which is a different device. It simply turns one ethernet port into multiple. That means your IP address is being handed to you by whatever handles it beyond your dorm room. So, it could be a case that your dorm internet is set up to only allow one IP to be handed out automatically. By hooking up a device to your switch, both your wireless router and your switch-connected computer are requesting IPs. 

 

When your computer is behind your wireless router, only one IP (the router itself) needs to be assigned an external IP, and everything else is handled correctly. 

 

tl;dr : You need to plug everything into the wireless router or move the switch behind your wireless router.

I think I understand it now, but then there are other problems:

1st: The other desktop was plugged into the gigabit switch and had no problem with the internet connectivity

2nd: if I move the switch behind the wireless router then I lose the 1Gbps connection from the dorm

 

And here's what I don't understand: how come the other desktop which was also plugged into the switch had no problem and this machine has the wrong IP and how to fix it.

[rustikles]

Oh, there's another computer on the switch? Again, because any device not behind your wireless router is being assigned an IP by the dorm equipment, there isn't really a way to know how they have things set up. Maybe it isn't just one IP they allow you via DHCP, but two (or more if you have other devices and they work).

 

My point is that there's nothing you can do to change what they have, short of asking them to assign a static IP for you new computer (which they probably won't do).

 

You did mention that you could manually assign your new computer an IP and it works fine. In that case, just leave it like that. So long as you remember to change that setting if you ever move the computer, it should be fine. 

[CptDavenport]

Oh, there's another computer on the switch? Again, because any device not behind your wireless router is being assigned an IP by the dorm equipment, there isn't really a way to know how they have things set up. Maybe it isn't just one IP they allow you via DHCP, but two (or more if you have other devices and they work).

 

My point is that there's nothing you can do to change what they have, short of asking them to assign a static IP for you new computer (which they probably won't do).

 

You did mention that you could manually assign your new computer an IP and it works fine. In that case, just leave it like that. So long as you remember to change that setting if you ever move the computer, it should be fine. 

No the problem is I unplugged the other computer from the switch and plugged in the new computer and it won't acquire the correct IP.

As far as I know my dorm allow plenty of devices out of that one connection as I have always used 3 devices behind the switch: 1 desktop 1 laptop and 1 wireless router.

[rustikles]

No the problem is I unplugged the other computer from the switch and plugged in the new computer and it won't acquire the correct IP.

As far as I know my dorm allow plenty of devices out of that one connection as I have always used 3 devices behind the switch: 1 desktop 1 laptop and 1 wireless router.

But your dorm sees a different MAC address for your new device, so it doesn't matter what you do or don't have plugged in. All I can tell you is reinstall your ethernet drivers or keep assigning your IP manually.