cmd/routedns/example-config/use-case-4.toml

# This config shows how to deal with multiple VPNs having their own DNS. It
# supports modifying queries for short hostnames such as prod-server1 into
# queries for server1.prod-domain.com and are routint to the correct DNS server.

# Lab DNS servers. Define both UDP and TCP, with TCP only used when responses
# are truncated.
[resolvers.prod-dns-udp]
address = "10.1.1.1:53"
protocol = "udp"

[resolvers.prod-dns-tcp]
address = "10.1.1.1:53"
protocol = "tcp"

[resolvers.test-dns-udp]
address = "10.2.1.1:53"
protocol = "udp"

[resolvers.test-dns-tcp]
address = "10.2.1.1:53"
protocol = "tcp"

# Try UDP first, if truncated use the alernative TCP one
[groups.prod-dns]
type = "truncate-retry"
resolvers = ["prod-dns-udp"]
retry-resolver = "prod-dns-tcp"

[groups.test-dns]
type = "truncate-retry"
resolvers = ["test-dns-udp"]
retry-resolver = "test-dns-tcp"

# Standard Cloudflare DoT, used for everything not destined to the lab
[resolvers.cloudflare-dot]
address = "1.1.1.1:853"
protocol = "dot"

[routers.router1]
routes = [
  { name = '(^|\.)prod-domain\.com\.$', resolver="prod-dns" }, # Prod VPN
  { name = '(^|\.)test-domain\.com\.$', resolver="test-dns" }, # Test VPN
  { resolver="cloudflare-dot" },                               # Everything else
]

[groups.append-domain]
type = "replace"
resolvers = ["router1"]
replace = [
  { from = '^prod-([^.]+\.)$', to = '${1}prod-domain.com.' },
  { from = '^test-([^.]+\.)$', to = '${1}test-domain.com.' },
]

[listeners.local-udp]
address = "127.0.0.1:53"
protocol = "udp"
resolver = "append-domain"

[listeners.local-tcp]
address = "127.0.0.1:53"
protocol = "tcp"
resolver = "append-domain"