[SOLVED] Can't connect to default gateway while connected VIA ethernet. (Other PC's can, including wifi devices)

Bobbii

Prominent
Jun 14, 2020
13
0
510
So brief summary of how my network is setup and the devices that are plugged in:

I have the main router/modem box connected directly into 3 PC's, one of them includes my current one, one is my old PC, and one is my sisters. I also have a box plugged into the jack that lets me run ethernet via the outlets from room to room so I can assume that is also connected via ethernet (I use this for a 4th PC). I have multiple devices on my network connect using Wi-Fi.

I recently purchased a new PC, and gave my brother my old one. I am using the same ethernet cable that I had on my old PC which I was able to use normally without issues.

My current problem is that my new PC does not allow me to access my Default Gateway. Even when I ping it from the command prompt I get "request timed out" infinitely. I was curious and tried pinging my other PC's, (the ones connected via ethernet) and was not able to get pings back either. Those had the same "request timed out" error.

I have no idea how to fix it and it is quite frustrating since I use this PC 24/7 for work and other things, and always used this as my main hub to control what happens on my network.

Is there an issue with my drivers? Am I being a simpleton and just have some kind of firewall?

If there is more information needed please let me know.
 
Solution
It almost has to be a firewall issue. Try to temporarily disable the firewall and see if it works.

This comes down to understanding how traffic really is transferred. Let say you had a rule that says deny 192.168.x.x. The traffic going to the internet does not actually have the ip of the gateway in the packet. The PC has looked up the mac address of the IP of the gateway and sends it to mac address. So even though the packet is going to the gateway the destination IP is actually some IP on the internet. In the ping packet it also is send to the mac address of the gateway but in this case it also has the destination IP of the gateway inside the packet.
So you are saying the pc does not work at all on ethernet.

If it works for internet then obviously it must be able to get to some gateway. Maybe there is a firewall rule limiting access to the local lan ip blocks.

Now if nothing works then it is more likely some driver issue or some configuration of the ethernet port.
 

Bobbii

Prominent
Jun 14, 2020
13
0
510
So you are saying the pc does not work at all on ethernet.

If it works for internet then obviously it must be able to get to some gateway. Maybe there is a firewall rule limiting access to the local lan ip blocks.

Now if nothing works then it is more likely some driver issue or some configuration of the ethernet port.

Ethernet works. The internet works just fine which is what confuses me... If my network driver wasn't working then I would assume my internet would be faulty too but it works how it should..
 
It almost has to be a firewall issue. Try to temporarily disable the firewall and see if it works.

This comes down to understanding how traffic really is transferred. Let say you had a rule that says deny 192.168.x.x. The traffic going to the internet does not actually have the ip of the gateway in the packet. The PC has looked up the mac address of the IP of the gateway and sends it to mac address. So even though the packet is going to the gateway the destination IP is actually some IP on the internet. In the ping packet it also is send to the mac address of the gateway but in this case it also has the destination IP of the gateway inside the packet.
 
Solution