From 3ddacad42a41516bc16b670a60a8e76f8f37e3bd Mon Sep 17 00:00:00 2001
From: Guy Resheff <gresheff@gmail.com>
Date: Thu, 27 Mar 2025 22:30:52 -0700
Subject: [PATCH] initial commit for docker dnsmasq and tailscale

---
 Dockerfile         | 13 +++++++++++++
 README.md          | 23 +++++++++++++++++++++++
 dnsmasq.conf       | 27 +++++++++++++++++++++++++++
 docker-compose.yml | 14 ++++++++++++++
 entrypoint.sh      |  4 ++++
 5 files changed, 81 insertions(+)
 create mode 100644 Dockerfile
 create mode 100644 dnsmasq.conf
 create mode 100644 docker-compose.yml
 create mode 100644 entrypoint.sh

diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..e8dda77
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,13 @@
+FROM ubuntu:22.04
+
+RUN apt-get update && apt-get install -y dnsmasq curl
+
+# Install Tailscale
+RUN curl -fsSL https://tailscale.com/install.sh | sh
+
+COPY dnsmasq.conf /etc/dnsmasq.conf
+COPY entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+ENTRYPOINT ["/entrypoint.sh"]
+CMD ["dnsmasq", "--keep-in-foreground", "--log-facility=-"]
diff --git a/README.md b/README.md
index 7ff04a3..8f76f1c 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,25 @@
 # local-dns-docker
 
+https://www.reddit.com/r/Tailscale/comments/1dql8a6/use_the_same_domain_name_on_home_network_and_on/
+
+What everybody has already said, but also use the tailnet IP of your DNS server as a global nameserver. I'll post my working steps:
+
+* Create a subnet router on your DNS host.
+
+1. On the DNS host you need to set --accept-dns=false
+2. advertise routes
+3. https://tailscale.com/kb/1019/subnets
+sudo tailscale up --accept-dns=false --advertise-routes=192.168.x.x/x
+
+* In tailscale Machines edit new host and allow new route(s)
+* In tailscale DNS, create a global namerserver:
+
+1. set it to the tailnet IP of your DNS server
+2. you can set split DNS here or you can just use your DNS for everything
+3. if u have android clients, check the slider to ignore local DNS
+
+* (optional) do the Linux enhancements mentioned on https://tailscale.com/kb/1019/subnets
+
+https://tailscale.com/kb/1019/subnets?tab=linux#connect-to-tailscale-as-a-subnet-router
+
+There is also a procedure to initially register the device with Tailscale server before this whole thing can work. Maybe I will document later. Not necessary as long as using the credentials in /DATA/AppData/tailscale/ so don't delete them.
diff --git a/dnsmasq.conf b/dnsmasq.conf
new file mode 100644
index 0000000..6b71fd7
--- /dev/null
+++ b/dnsmasq.conf
@@ -0,0 +1,27 @@
+# Don't use /etc/hosts or /etc/resolv.conf
+no-hosts
+no-resolv
+
+# Listen on all interfaces
+#interface=*
+interface=eth0
+interface=tailscale0
+
+# Resolve *.local to 192.168.1.16
+address=/.local/192.168.1.16
+
+# Forward other queries to 192.168.1.1
+server=192.168.1.1
+
+# Log queries
+log-queries
+log-facility=-
+
+# Don't use /etc/hosts
+no-hosts
+
+# Don't act as a DHCP server
+no-dhcp-interface=
+
+# Bind to all interfaces
+bind-interfaces
diff --git a/docker-compose.yml b/docker-compose.yml
new file mode 100644
index 0000000..8a639d4
--- /dev/null
+++ b/docker-compose.yml
@@ -0,0 +1,14 @@
+version: '3'
+services:
+  dns-server:
+    container_name: dns-server
+    build: .
+    cap_add:
+      - NET_ADMIN
+      - SYS_MODULE
+    devices:
+      - /dev/net/tun:/dev/net/tun
+    volumes:
+      - /DATA/AppData/dns-docker:/var/lib/tailscale
+    network_mode: host
+    restart: unless-stopped
diff --git a/entrypoint.sh b/entrypoint.sh
new file mode 100644
index 0000000..c6b3753
--- /dev/null
+++ b/entrypoint.sh
@@ -0,0 +1,4 @@
+#!/bin/bash
+tailscaled &
+tailscale up --accept-dns=false --advertise-routes=192.168.1.0/24
+exec "$@"