nsupdate-web

Simple DDNS (dynamic DNS) web API service with nsupdate (8).

It's a small Python 3 library and companion script accepting HTTP requests and changing DNS records on BIND server with nsupdate (8).

Features

• Update IP addresses with a simple curl or wget command
• Support multiple A and/or AAAA records for each domain name
• Pure Python, standard library only (aside from tests)

Usage

See ./ddns-server.py --help

Start script

Serving dyn.example.com on 127.0.0.1:8080, updating named on localhost using a host file:

$ ./ddns-server.py -l 127.0.0.1 -p 8080 -k hosts.json -d dyn.example.com

hosts.json is a JSON file which contains all hostname-password pairs:

{
  'test': 'pwd123',
  'elder': 'mogic'
}

Serving dyn.example.com on 127.0.0.1:8080, updating named on ns1.example.com using a key file:

./ddns-server.py -d dyn.example.com -K ./Kdyn.example.com.+123+12345.key -s ns1.example.com

Update addresses

When using a host file:

$ curl https://test:pwd123@dyn.example.com/update
> success
$ dig +short test.dyn.example.com
> 198.51.100.5

$ curl https://test:pwd123@dyn.example.com/update?ip=192.0.2.8
> success
$ dig +short test.dyn.example.com
> 192.0.2.8

$ curl https://elder:mogic@dyn.example.com/update?ip=2001:DB8::1968:08:17&ip=192.0.2.8&ip=198.51.100.5
> success
$ dig +short elder.dyn.example.com aaaa
> 2001:db8::1968:8:17
$ dig +short elder.dyn.example.com a
> 192.0.2.8
  198.51.100.5

Without a host file, if authentication is not needed:

$ curl "http://dyn.example.com:8080/update?name=test&ip=192.0.2.8"
> success
$ dig +short test.dyn.example.com
> 192.0.2.8

Install

From a git clone:

$ python setup.py install

After installation, ddns-server will be in $PATH

Prerequisites

• Python 3 (for running this script)
• BIND 9 (for serving zones)
• Nginx (for rewriting URLs and HTTPS support)
• nsupdate (possibly included in BIND)

Note that this script only communicate with BIND via nsupdate, so you have to configure your BIND server allowing updating records with the nsupdate tool.

Run as a service

Add this systemd service file as /etc/systemd/system/ddns-server.service:

[Unit]
Description=DDNS HTTP update service.

[Service]
Type=simple
User=named
Group=named
ExecStart=/usr/bin/python3 /path/to/ddns-server.py -k /path/to/hosts.json -p 8080 -d dyn.example.com
ExecStopPost=/usr/bin/rndc sync -clean dyn.example.com

[Install]
WantedBy=multi-user.target

Enable and start:

$ sudo systemctl enable ddns-server
$ sudo systemctl start ddns-server

Nginx configuration

Here is a example:

server {
	listen 443 ssl http2;
    
    location / {
    	root /srv/http/ddns;
        index index.html;
        # Provide some helpful explanations here.
    }
    
    location = /update {
    	include proxy_params;
        proxy_pass http://localhost:8080;
    }
    
    # To be compatible with HE.net's DDNS clients/scripts. 
    rewrite ^/nic/update$ /update last;
}