Hello! I (tried, at least) converted an old laptop to a Debian home server, and I was trying to set up duckdns.org and to enable port forwarding on my router. internet connection was working, I installed packages, docker, immich, etc, and then suddenly (I don't know exactly when) it refuses to connect to the internet. It does connect to local addresses (I can ssh into it) but ping google.com and any other internet-involving command fail. I had set up a rule on the router to forward port 80 to the device's port 80, but I then removed the rule and it still does not connect to the internet. I rebooted the router but nothing changed. Any idea what could be? the router is a Vodafone router.
I changed the hostname to debianserver but on the router it is still written debian. Also, it's the only device with unknown ipv6
thanks in advance!
EDIT: I rebooted again the server, and now ipv6 is not unknown anymore, and the hostname is correct. however, it still does not connect to the internet
EDIT 2:
only one device (debianserver) has this problem, other devices work as before
EDIT 3:
I don't know if it's useful or not, but if I boot a live debian USB in the server internet works
~~SOLUTION:~~ aaaaand no it does not work, after restarting docker it seems to work because all the brodges are yet to be created and it takes some time, after like 30 seconds it does not work as before :(
- edit the file
/lib/systemd/system/docker.service - append the flag
--bip=192.168.3.1/24toExecStart=.... systemctl daemon-reloadsystemctl restart docker
docker was the fucker that messed everything up and made me lose a few hours!
EDIT 4:
it seems that ip route flush 0/0 restores the internet connectivity until reboot... I don't know what does this means but can be a temporary workaround I guess? I really have no idea how to solve this
FINAL EDIT: I gave up. I removed debian and installed fedora, and now it all works like a charm
Does
ping 8.8.8.8work? (To check if it's DNS)What's
ip route showsay? (Just to try to narrow down whether it's an issue with the server's config or the router's)What's
traceroute 8.8.8.8display?thanks for the answer!
ping 8.8.8.8fails, and I don't have traceroute installed (and no internet to install it)This is kind of a nutty network config. It looks like docker is setting up extra default routes, which I could easily see fouling everything up. As a first experiment (warning, this may ruin your networking until the next reboot):
... and see if that makes things work (start with
ping 192.168.1.1andping 8.8.8.8). If that solves the problem, then I think something about your docker config is adding stuff to your networking that's causing the problem; maybe remove/disable docker completely and then re-add docker things one at a time to see where the problem comes in.okay, I thought to have solved the problem but I was wrong, here I go again. When I
docker compose up -dthe immich server (the only one I have installed) all those routes are created, and apparently some of them conflicts with something else and now my host has no internet connection. however it seems thatip route flush 0/0solves the problem until the reboot, which is strange. the other command returnsRTNETLINK answers: File existsHm. Yeah, that's weird. The default routes you're seeing should basically never exist, so it sounds like there's some kind of manual network config happening inside the Docker container that's creating a broken network.
What does
docker network inspect [network]say for each of your Docker networks (substituting each Docker network for "[network]")? What's the network section ofdocker-compose.ymllook like?Try removing all the superfluous default routes.