[Nix-dev] Failed to add route because network is unreachable

[Bas van Dijk]

Dear Nixers,

I've a slightly off-topic question but since I know there are some
excellent Unix networking experts on this list I hope to get a pointer
in the right direction.

After some changes in my networking setup (I added an IP address to my
eth0 interface) my strongswan VPN service fails to add a route to my
routing table (it used to work before):

installing route: 10.180.0.0/24 via 136.243.17.1 src 172.16.48.17 dev eth0
received netlink error: Network is unreachable (101)

If I manually try to add the route I get the same error message:

# ip route add  10.180.0.0/24 via 136.243.17.1 src 172.16.48.17 dev eth0
RTNETLINK answers: Network is unreachable

I've asked[1] the same question on the strongswan mailing list but
haven't found a solution yet.

My network settings are fairly simple (note I'm deploying my machine
using nixops to Hetzner):

  deployment = {
    targetEnv = "hetzner";
    hetzner = {
      mainIPv4  = "136.243.17.41";
      ...
    };
  };

  networking = {
    enableIPv6 = false;
    useDHCP = false;

    interfaces.eth0.ip4 = [
      { address = "136.243.25.125"; prefixLength = 32; }
      { address = "136.243.25.108"; prefixLength = 32; }
      { address = "172.16.48.17";   prefixLength = 28; }
    ];

    firewall = {
      enable    = true;
      allowPing = true;
      allowedTCPPorts = [ ... ];
    }
  };

Any idea why I can't add that route?

Regards,

Bas

[1] https://lists.strongswan.org/pipermail/users/2015-April/007935.html