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knot-resolver: secondary address for uncensored DNS

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This commit is contained in:
Casper V. Kristensen 2024-10-07 23:45:22 +02:00
parent 9fd6e50710
commit a323eb77b9
2 changed files with 42 additions and 19 deletions
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59
hosts/delta/knot-resolver.nix
View file

@ -21,23 +21,52 @@
# https://knot-resolver.readthedocs.io/en/stable/daemon-scripting.html
services.kresd = {
enable = true;
# For maximum performance, there should be as many kresd processes as there
# For maximum performance there should be as many kresd processes as there
# are available CPU threads.
# We double it to account for the SYSTEMD_INSTANCE scheme below.
# https://knot-resolver.readthedocs.io/en/stable/systemd-multiinst.html
instances = 2;
instances = 4;
extraConfig =
# lua
''
-- Explicitly listen to DNS/DoH/DoT on the external interface(s). This
-- allows systemd-resolved to listen on localhost as on every other system.
-- Explicitly only listen on external addresses to allow
-- systemd-resolved to use localhost:53 as on every other system.
local ipv4 = "159.69.4.2"
local ipv6 ="2a01:4f8:1c0c:70d1::1"
net.listen(ipv4, 53, {kind = "dns"})
net.listen(ipv6, 53, {kind = "dns"})
net.listen(ipv4, 853, {kind = "tls"})
net.listen(ipv6, 853, {kind = "tls"})
net.listen(ipv4, 443, {kind = "doh2"})
net.listen(ipv6, 443, {kind = "doh2"})
local ipv6_1 = "2a01:4f8:1c0c:70d1::1"
local ipv6_2 = "2a01:4f8:1c0c:70d1::2"
-- We want to apply different query policies based on the listening
-- address, but doing so is difficult. Instead, we define bind address
-- and query policies together based on the systemd instance number.
-- https://knot-resolver.readthedocs.io/en/stable/systemd-multiinst.html#instance-specific-configuration
local systemd_instance = tonumber(os.getenv("SYSTEMD_INSTANCE"))
if systemd_instance % 2 == 0 then
-- IPv4 and IPv6-1: Block spam and advertising domains.
net.listen(ipv4, 53, {kind = "dns"})
net.listen(ipv6_1, 53, {kind = "dns"})
net.listen(ipv4, 853, {kind = "tls"})
net.listen(ipv6_1, 853, {kind = "tls"})
net.listen(ipv4, 443, {kind = "doh2"})
net.listen(ipv6_1, 443, {kind = "doh2"})
-- https://knot-resolver.readthedocs.io/en/stable/modules-policy.html#response-policy-zones
policy.add(
policy.rpz(
-- Beware that cache is shared by *all* requests. For example, it is
-- safe to refuse (policy.DENY) answer based on who asks the resolver,
-- but trying to serve different data to different clients (policy.ANSWER)
-- will result in unexpected behavior.
-- https://knot-resolver.readthedocs.io/en/stable/modules-view.html:
policy.DENY,
"${pkgs.runCommand "stevenblack-blocklist-rpz" {} ''grep '^0\.0\.0\.0' ${pkgs.stevenblack-blocklist}/hosts | awk '{print $2 " 600 IN CNAME .\n*." $2 " 600 IN CNAME ."}' > $out''}"
)
)
else
-- IPv6-2: Don't censor anything.
-- This is primarily for the tor exit relay, since not censoring
-- anything is kind of the whole point of tor.
net.listen(ipv6_2, 53, {kind = "dns"})
net.listen(ipv6_2, 853, {kind = "tls"})
net.listen(ipv6_2, 443, {kind = "doh2"})
end
-- TLS certificate for DoT and DoH
-- https://knot-resolver.readthedocs.io/en/stable/daemon-bindings-net_tlssrv.html
net.tls(
@ -53,14 +82,6 @@
-- expire, they get refreshed.
-- https://knot-resolver.readthedocs.io/en/stable/modules-predict.html
modules.load("predict")
-- Block spam and advertising domains
-- https://knot-resolver.readthedocs.io/en/stable/modules-policy.html#response-policy-zones
policy.add(
policy.rpz(
policy.ANSWER({ [kres.type.A] = {rdata=kres.str2ip("0.0.0.0"), ttl = 600} }),
"${pkgs.runCommand "stevenblack-blocklist-rpz" {} ''grep '^0\.0\.0\.0' ${pkgs.stevenblack-blocklist}/hosts | awk '{print $2 " 600 IN CNAME .\n*." $2 " 600 IN CNAME ."}' > $out''}"
)
)
-- Test domain to verify DNS server is being used
policy.add(
policy.domains(

2
hosts/delta/network.nix
View file

@ -5,7 +5,9 @@
networks."10-lan" = {
matchConfig.Name = "enp1s0";
address = [
# NOTE: Default outgoing address is the LAST address in the list
"159.69.4.2/32"
"2a01:4f8:1c0c:70d1::2/64"
"2a01:4f8:1c0c:70d1::1/64"
];
routes = [