Network configuration problems
Network configuration problems
I'm managing pihole on a Docker container on my Ubuntu server. I was forwarding ports to host a Minecraft server, but after trying to access them, both my main PC and the server show the same public IP address on sites like ipchicken or canyouseeme.org. I think this is just a sign of something else, not the root issue, but it's preventing any external connections. I've looked at the query logs in pihole, but no blocked requests appear. I'm unsure what to do next and don't know where to start. Help would be appreciated.
This process explains how routing functions. Your home internet link uses just one public IP address, while each device on your local network has its own unique address within the LAN. The router directs the data to the appropriate location using a technique known as "NAT." You must redirect the specific port through the device managing NAT—typically your router or modem.
They rely on Network Address Translation. This method has been part of internet sharing since Windows 98, even before that. To open ports, adjust the devices to have a fixed IP behind the router so traffic always goes through the same endpoint. Run "arp -a" to see what machines are visible locally and confirm your IP allows firewall access for those ports. Essentially: your PC connects to port 420, the router forwards it to 192.168.1.42:420. You’ll likely share the same public IP across your network devices. If connecting inside your local area, use your private IP instead of the public one.
I understand the server uses a fixed IP address, and I've tried it with Minecraft before. I forwarded the port in the same way as other services. Probably I should check the firewall configuration to see what's happening. From what I remember, everything worked smoothly before I enabled pihole, so I'll investigate that first. I didn't realize public IPs were the same across devices on the local network, though looking back it seems clear.
After further research, I discovered several points:
1. My pihole might not be connected to this problem.
2. I’m unsure if it’s a firewall issue since Ubuntu doesn’t have one by default, though I tried enabling it and opened the needed ports—still no success.
3. Checking port availability on external sites shows connection failures instead of blocks or rejections.
4. Enabling DMZ host on my router only makes the port available after a delay, which isn’t a fix but gives clues.
5. Others on forums mention similar timeout issues after recently switching routers, which seems relevant to my situation.
I’m still trying to piece these together, as most of what I found doesn’t clearly solve my concern.
Interesting finding. Enabling DMZ lets the port work normally until I attempt to connect to the Minecraft server. It remains open until I actually try joining, which is puzzling. I’m thinking a firewall might be involved, but it’s hard to pinpoint exactly what’s causing it.