38 lines
2.0 KiB
Nix
38 lines
2.0 KiB
Nix
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{ ... }:
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{
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# use systemd's stub resolver.
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# /etc/resolv.conf isn't sophisticated enough to use different servers per net namespace (or link).
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# instead, running the stub resolver on a known address in the root ns lets us rewrite packets
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# in the ovnps namespace to use the provider's DNS resolvers.
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# a weakness is we can only query 1 NS at a time (unless we were to clone the packets?)
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# there also seems to be some cache somewhere that's shared between the two namespaces.
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# i think this is a libc thing. might need to leverage proper cgroups to _really_ kill it.
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# - getent ahostsv4 www.google.com
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# - try fix: <https://serverfault.com/questions/765989/connect-to-3rd-party-vpn-server-but-dont-use-it-as-the-default-route/766290#766290>
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services.resolved.enable = true;
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# without DNSSEC:
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# - dig matrix.org => works
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# - curl https://matrix.org => works
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# with default DNSSEC:
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# - dig matrix.org => works
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# - curl https://matrix.org => fails
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# i don't know why. this might somehow be interfering with the DNS run on this device (trust-dns)
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services.resolved.dnssec = "false";
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networking.nameservers = [
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# use systemd-resolved resolver
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# full resolver (which understands /etc/hosts) lives on 127.0.0.53
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# stub resolver (just forwards upstream) lives on 127.0.0.54
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"127.0.0.53"
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];
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# nscd -- the Name Service Caching Daemon -- caches DNS query responses
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# in a way that's unaware of my VPN routing, so routes are frequently poor against
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# services which advertise different IPs based on geolocation.
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# nscd claims to be usable without a cache, but in practice i can't get it to not cache!
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# nsncd is the Name Service NON-Caching Daemon. it's a drop-in that doesn't cache;
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# this is OK on the host -- because systemd-resolved caches. it's probably sub-optimal
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# in the netns and we query upstream DNS more often than needed. hm.
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# TODO: run a separate recursive resolver in each namespace.
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services.nscd.enableNsncd = true;
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}
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