Fritz!Box port forwarding is not working properly

Question

I have a question about port forwarding with FRITZ!Box.

When I port forward for my server, it works for a while, but after 3/4 days people can't join my server anymore. It's really weird and I have to port forward again.

I had the same problem today, but this time, the port forward didn't work anymore. I did the same thing as before as far as I know.

Could someone explain what is wrong?

Solution

I had similar problems with my Fritz 7490. In my findings, it's related not to the port forwarding itself, but the Fritz notion and behaviour of the destination machine ("to computer" field in your screenshot).

Example: If the same machine (one MAC address) boots up different operating systems/hostnames, Fritz gets confused, and that affects port forwarding. Also if you use the "specific IP address" the port forwarding configuration, but then later change/add a machine config with the same IP address, the port forwarding changes to point to that machine "name" instead of the IP.

In summary: try to clean up the machine/MAC list in Fritz (in "Home Network > Home Network Overview > Network Connections"), making sure there's no conflicts, and re-create the forwarding rules. That should fix it.

Comments

[user.dz]

John the 1st picture link is missing, could you edit question and add it?

[Mario]

You don't have to black out local LAN IPs. Noone is able to do anything bad with them. But either way this looks fine to me. Have you checked whether your FIrewall blocks incoming connections for the Minecraft server?

[Vomit IT - Chunky Mess Style]

What's your fritz!box model number and do you know the firmware version it's running? Quick Thoughts: 1. Perhaps you need to update the firmware and do a power cycle of the device due to memory fragmentation. 2. If you still have issues you may consider factory resetting the device and then seeing how it works after a firmware update if applicable. 3. Lastly, you could run a Wireshark trace when it does and when it does not work and compare to see if anything there gives further clue at that level.

[K. Biermann]

This is still relevant 😕 I'm using a dual-boot-system (Windows and macOS) and it keeps forgetting the rules if I change the OS (not always; but ~every second reboot)...