Broken network while installing NixOS via the minimal ISO image on a VPS

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1

Hello. I’m want to install NixOS on a VPS hosting that doesn’t offer NixOS installations out of the box, but they support booting from an ISO image. When I mounted and booted the VPS into the installation ISO, I noticed two networking issues:

  • I couldn’t resolve any hostname;
  • I couldn’t succesfully ping any public IP either.

I looked up the IP addresses assigned to my VPS by the hoster in the admin panel:

IP Address Network Mask Gateway
95.132.101.114 255.255.255.0 95.132.101.1

(^ these are fake addresses)

While running ip address show ens3 and ip routes showed a different address and a gateway were set up for the interface:

# ip address show ens3
     # [...snip...]
     # notice /16 prefix doesn't match the correct network mask
     inet 168.253.182.161/16 brd 168.253.255.255 scope global prefix noprefixroute ens3
     # [...snip...]

# ip routes
default dev ens3 scope link src 168.253.182.161 metric 1001002
# [...snip...]

(^ these are fake addresses)

Also, /etc/resolv.conf had no nameserver entries.

I believe dhcpcd is responsible for setting up the network in the installer, so I disabled it and added the IP address and the default gateway route by hand:

# systemctl stop dhcpcd
# ip address add 95.132.101.114/24 broadcast 95.132.101.255 dev ens3
# ip route add default via 95.132.101.1 dev ens3 proto static metric 100

At this point ping-ing public IPs works, but hostname resolution doesn’t. Adding CloudFlare and Google resolvers to /etc/resolv.conf fixed that:

# echo -e "nameserver 1.1.1.1\nnameserver 8.8.8.8\nnameserver 8.8.4.4" >> /etc/resolv.conf

Then I could proceed with the installation.

The question is why the installer had non-functional networking setup? Is this an installer issue that can be fixed? Or is the hosting company’s infrastructure to blame?

Bonus question: I’m a noob when it comes to networking and while I managed to set it up in the end, is the setup correct/optimal? Is there any way I could handle this issue better? I haven’t found any mentions of related issues in the manual (though it’s probably out of the scope of the manual).

Thanks in advance!

2 Likes
2

I have just successfully installed NixOS on the VPS, and the same issue with DHCP networking setup exists on the installed system, which I solved by static network configuration as per Networking docs:

{ config, pkgs, ... }:

{
  # [...snip...]
  networking.interfaces.ens3 = {
    useDHCP = false;
    ipv4.addresses = [
      { address = "95.132.100.114"; prefixLength = 24; }
    ];
  };
  networking.defaultGateway = "95.132.100.1";
  networking.nameservers = [
    "1.1.1.1"
    "8.8.8.8"
    "8.8.4.4"
  ];
  # [...snip...]
}
1 Like
3

I have also just had the same issue with the ISO Minimal on 9/17/2024, I also had to set my IP manually on the provider I am using. IPv4 address gets assigned on other Linux OS’s just fine via DHCP.

Over a year later this issue persists, I am not sure what is broken or even if it is, but it is annoying as a new user and take a good amount more time for me to troubleshoot why everything is not working and that the installer NixOS Manual wasn’t working.

I have spend over 2+ hours stumbling my way about, to figure out how to fix it just so I could continue to install NixOS.

As a new NixOS user not even making it past the install before I ran into a brick wall is not a good first time impression.

4

Could you share which provider this is? Not to minimize your issue here, but this is the first I’ve heard of this, and there are plenty of NixOS-on-VPS systems set up by noobs and experts alike. This sounds like a very specific thing.

5

I was using reliablesite.net, this was a bare metal server I was installing onto. I did not link the provider because usually that is discouraged in forums.

6

Hard to debug unless someone with a server in that provider’s network checks things out for a while. If you have the time and energy, I’m sure a thorough explanation of what is wrong with the default networking config would be appreciated and met with a fix in due time.

Things to check with the broken networking:

  • dhcpcd logs
  • dmesg
  • full contents of journalctl --boot -xe

To be clear, what you’re running into is that dhcp assigns the wrong IP address? Hard to see how that could be anything other than a network level issue, but I suppose there’s more to it if it works on other distros…