This repo is archived. It's not being maintained and may no longer work.

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Local Address DNS

What is this?

You don't always know the IP address a network device will be assigned on your local network (and don't always have access to / can be bother with MAC based DHCP assignments). local-address-dns turns a DNS entry like local.pi.example.com into your local IP address.

local-address-dns is a DNS server. When it receives a request, it fetches the local IP address from a local-address-dns-client (avaliable for Raspberry Pi at local-address-dns-client-rpi).

For more information about the inspiration and implementation, see my blog post, Easy access to my Pi on a local network.

Command Line Arguments

DNS Zone

The DNS Zone is the DNS name you want to go to access your local network device. An example is local.pi.example.com.

Setting up a DNS record for the DNS zone

Your domain's DNS provider needs to point to your server so requests attempting to get the address of the device are sent to local-address-dns. Login to your DNS provider and setup a NS record with the name set to your DNS zone, and the value set to the server's hostname. For example, an NS record where local.pi.example.com points to server.example.com.

Local address client URL

The local address client URL is the URL to fetch the local IP address from (i.e.: a local-address-dns-client instance). e.g.: If you have a VPN tunnel to access the local network device at pi.example.com and the local-address-dns-client runs on port 3000, then this would be http://pi.example.com:3000.

Environment variable based overrides

The TTL and Port can be overridden by setting environment variables.

TTL

This is the time to live of the DNS record, i.e.: how long the DNS entry for the local address can be cached.

The default value is 5 minutes (300 seconds), but this can be overridden by setting the LOCAL_ADDRESS_DNS_TTL environment variable with the new TTL in seconds.

Port

This is the UDP port used for the DNS server.

The default value is port 53, but this can be overridden by setting the LOCAL_ADDRESS_DNS_PORT environment variable with the new port number.

Using Docker

Building

Build with docker build -t jordancrawford/local-address-dns ..

Running

Run with docker run -d -p 53:53/udp --restart always --name local-address-dns jordancrawford/local-address-dns [DNS zone] [local address client URL]

Using Directly

Ensure NodeJS is installed on your system and run: node server [DNS zone] [local address client URL]. The default port is 53 so requires root privledges. Run the command with sudo to obtain these.