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Secure DNS and Captive Portal
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'''Encrypted DNS''' protocols aim to address this hole by encrypting queries and responses in transit between DNS resolvers and clients; the most widely deployed ones are [[wikipedia:DNS over HTTPS|DNS over HTTPS]] (DoH), [[wikipedia:DNS over TLS|DNS over TLS]] (DoT), and [https://dnscrypt.info/ DNSCrypt].
'''Encrypted DNS''' protocols aim to address this hole by encrypting queries and responses in transit between DNS resolvers and clients; the most widely deployed ones are [[wikipedia:DNS over HTTPS|DNS over HTTPS]] (DoH), [[wikipedia:DNS over TLS|DNS over TLS]] (DoT), and [https://dnscrypt.info/ DNSCrypt].


NixOS has modules for multiple encrypted DNS proxies, including [https://github.com/DNSCrypt/dnscrypt-proxy dnscrypt-proxy 2] and [https://dnsprivacy.org/wiki/display/DP/DNS+Privacy+Daemon+-+Stubby Stubby]. <code>services.dnscrypt-proxy2</code> is generally recommended, as it has the widest protocol and feature support, and is written in a memory-safe language.
NixOS has modules for multiple encrypted DNS proxies, including [https://github.com/DNSCrypt/dnscrypt-proxy dnscrypt-proxy 2], [https://github.com/AdguardTeam/dnsproxy dnsproxy] and [https://dnsprivacy.org/wiki/display/DP/DNS+Privacy+Daemon+-+Stubby Stubby]. <code>services.dnscrypt-proxy2</code> is generally recommended, as it has the widest protocol and feature support, and is written in a memory-safe language. For DNS over TLS (DoT) support, <code>services.dnsproxy</code> can be used. Detailed comparison of DNS proxies can be found on [https://wiki.archlinux.org/title/Domain_name_resolution#DNS_servers ArchLinux Wiki].


== Setting nameservers ==
== Setting nameservers ==
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If you'd prefer to keep using resolvconf then you can set <code>networking.resolvconf.useLocalResolver</code> instead. Note that it uses the IPv4 loopback address only.
If you'd prefer to keep using resolvconf then you can set <code>networking.resolvconf.useLocalResolver</code> instead. Note that it uses the IPv4 loopback address only.
== Secure DNS and Captive Portal ==
Secure DNS will break most captive portals like those of public or hotel wifi access points, resulting in inability to gain internet access through such access points.
In that case, use <code>networkctl status ${wlan interface}</code> to show the default DNS provided by the network, and temporarily change nameserver inside <code>/etc/resolv.conf</code> from <code>127.0.0.53</code> to the provided one.
Alternatively, if you have Chromium installed, you can use the <code>programs.captive-browser.enable</code> Chromium wrapper, which is "Dedicated Chrome instance to log into captive portals without messing with DNS settings".


== dnscrypt-proxy2 ==
== dnscrypt-proxy2 ==


=== Example configuration ===
=== Basic configuration ===
 
<syntaxhighlight lang="nixos">
<syntaxhighlight lang="nixos">
let
let
   hasIPv6Internet = true;
   hasIPv6Internet = true;
  StateDirectory = "dnscrypt-proxy";
in
in
{
{
  # See https://wiki.nixos.org/wiki/Encrypted_DNS
   services.dnscrypt-proxy2 = {
   services.dnscrypt-proxy2 = {
     enable = true;
     enable = true;
    # See https://github.com/DNSCrypt/dnscrypt-proxy/blob/master/dnscrypt-proxy/example-dnscrypt-proxy.toml
     settings = {
     settings = {
      # Use servers reachable over IPv6 -- Do not enable if you don't have IPv6 connectivity
      ipv6_servers = hasIPv6Internet;
      block_ipv6 = ! hasIPv6Internet;
      require_dnssec = true;
       sources.public-resolvers = {
       sources.public-resolvers = {
         urls = [
         urls = [
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           "https://download.dnscrypt.info/resolvers-list/v3/public-resolvers.md"
           "https://download.dnscrypt.info/resolvers-list/v3/public-resolvers.md"
         ];
         ];
         cache_file = "/var/lib/dnscrypt-proxy/public-resolvers.md";
         minisign_key = "RWQf6LRCGA9i53mlYecO4IzT51TGPpvWucNSCh1CBM0QTaLn73Y7GFO3"; # See https://github.com/DNSCrypt/dnscrypt-resolvers/blob/master/v3/public-resolvers.md
         minisign_key = "RWQf6LRCGA9i53mlYecO4IzT51TGPpvWucNSCh1CBM0QTaLn73Y7GFO3";
         cache_file = "/var/lib/${StateDirectory}/public-resolvers.md";
       };
       };
      # Use servers reachable over IPv6 -- Do not enable if you don't have IPv6 connectivity
      ipv6_servers = hasIPv6Internet;
      block_ipv6 = ! (hasIPv6Internet);
      require_dnssec = true;
      require_nolog = false;
      require_nofilter = true;


       # If you want, choose a specific set of servers that come from your sources.
       # If you want, choose a specific set of servers that come from your sources.
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   };
   };


   systemd.services.dnscrypt-proxy2.serviceConfig = {
   systemd.services.dnscrypt-proxy2.serviceConfig.StateDirectory = StateDirectory;
    StateDirectory = "dnscrypt-proxy";
    # If you're trying to set up persistence with dnscrypt-proxy2 and it isn't working
    # because of permission issues, try the following:
    # StateDirectory = lib.mkForce "";
    # ReadWritePaths = "/var/lib/dnscrypt-proxy"; # Cache directory for dnscrypt-proxy2, persist this
  };
}
}
</syntaxhighlight>
</syntaxhighlight>
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See [https://github.com/DNSCrypt/dnscrypt-proxy/blob/master/dnscrypt-proxy/example-dnscrypt-proxy.toml the upstream example configuration file] for more configuration options.
See [https://github.com/DNSCrypt/dnscrypt-proxy/blob/master/dnscrypt-proxy/example-dnscrypt-proxy.toml the upstream example configuration file] for more configuration options.


=== Blocklist ===
Fetch a blocklist file (e.g. oisd) as a flake input:<syntaxhighlight lang="nix">
# flake.nix
{
  inputs = {
    oisd = {
      url = "https://big.oisd.nl/domainswild";
      flake = false;
    };
    # Your configuration
  };


==== Local network - Forwarding rules ====
  outputs =
    { self, nixpkgs, oisd, ... }@inputs:
    {
      # Your configuration
    };
}
</syntaxhighlight><syntaxhighlight lang="nixos">
{ config, lib, pkgs, inputs, ... }:
let
  blocklist_base = builtins.readFile inputs.oisd;
  extraBlocklist = '''';
  blocklist_txt = pkgs.writeText "blocklist.txt" ''
    ${extraBlocklist}
    ${blocklist_base}
  '';
in
{
  services.dnscrypt-proxy2.settings.blocked_names.blocked_names_file = blocklist_txt;
}


</syntaxhighlight>
=== Local network - Forwarding rules ===
Maybe you'd like queries for your local domain to go to your router, and not to an upstream DNS resolver. By doing so, names of your local online devices can be found. For this you have to create a file with [https://github.com/DNSCrypt/dnscrypt-proxy/blob/master/dnscrypt-proxy/example-forwarding-rules.txt forwarding rules] which you then include in your config:
Maybe you'd like queries for your local domain to go to your router, and not to an upstream DNS resolver. By doing so, names of your local online devices can be found. For this you have to create a file with [https://github.com/DNSCrypt/dnscrypt-proxy/blob/master/dnscrypt-proxy/example-forwarding-rules.txt forwarding rules] which you then include in your config:


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Note that you can still access the other DNS server locally through the non-loopback interface (e.g. by using your server's external IP).
Note that you can still access the other DNS server locally through the non-loopback interface (e.g. by using your server's external IP).
== dnsproxy ==
dnsproxy is a simple DNS proxy server with the widest protocol support.
=== Example configuration ===
<syntaxhighlight lang="nix">
{
  services.dnsproxy = {
    enable = true;
    settings = {
      # Plain DNS upstream
      upstream = [ "1.1.1.1:53" ];
      # DNS over TLS upstream
      upstream = [ "tls://dns.adguard.com" ];
      # DNS over HTTPS upstream
      upstream = [ "https://dns.adguard.com/dns-query" ];
      listen-addrs = [ "0.0.0.0" ];
      # Plain DNS server
      listen-ports = [ 53 ];
      # DNS over TLS server
      tls-port = [ 853 ];
      # DNS over HTTPS server
      https-port = [ 443 ];
      # Certificate for encrypted DNS server
      tls-crt = "/var/lib/acme/example.org/fullchain.pem";
      tls-key = "/var/lib/acme/example.org/key.pem";
    };
    # Additional launch flags
    flags = [ "--verbose" ];
  };
}
</syntaxhighlight>


== Stubby ==
== Stubby ==
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</syntaxhighlight>
</syntaxhighlight>


[[Category: Networking]]
[[Category:Networking]]
[[Category:DNS]]
Retrieved from "https://wiki.nixos.org/wiki/Encrypted_DNS"