mirror of
https://codeberg.org/mclemens/qrz.is.git
synced 2024-11-02 18:47:44 -04:00
108 lines
3.6 KiB
Markdown
108 lines
3.6 KiB
Markdown
---
|
||
title: Dynamic DNS for NSD
|
||
type: post
|
||
author: micha
|
||
date: 2018-05-03T02:26:11+00:00
|
||
url: /dynamic-dns-for-nsd/
|
||
tags:
|
||
- DNS
|
||
- OpenBSD
|
||
- Linux
|
||
- Software
|
||
|
||
---
|
||
# Introduction
|
||
|
||
nsd-dyndns is a simple script that adds dynamic DNS dunctionality to NSD (authoritative DNS name server).
|
||
|
||
# Requirements
|
||
|
||
The following is required or suggested:
|
||
|
||
* OpenBSD (or another BSD or some Linux distro) with HTTPD and NSD installed (pkg_add nsd), configured and running
|
||
* (sub-)domain for your webserver. Needed for updating the NS record of your actual DynDNS domain.
|
||
* In this example: _update.example.com_
|
||
* (sub-)domain that is updated dynamically.
|
||
* In this example: _dyn.example.com_
|
||
* A router capable of sending custom GET-requests to your DynDNS server.
|
||
* In this example: A FritzBox
|
||
|
||
# Installation
|
||
|
||
## Configure your HTTPD
|
||
|
||
Add the following new virtual host to your _/etc/httpd.conf_:
|
||
|
||
server "update.example.com" {
|
||
listen on $ext_addr port 80
|
||
root "/htdocs/dyndns"
|
||
log access dyndns.log
|
||
}
|
||
|
||
Create an empty _update.html_:
|
||
|
||
# mkdir /var/www/htdocs/dyndns/
|
||
# touch /var/www/htdocs/dyndns/update.html
|
||
|
||
After reloading HTTPD, try to access [http://update.example.com/update.html] The request should show up in _/var/www/logs/dyndns.log_
|
||
|
||
## **Create a zone file for dyn.example.com**
|
||
|
||
Create a new zone file (e.g. at _/var/nsd/zones/dyn.example.com.zone_) with the following content
|
||
|
||
$ORIGIN example.com.
|
||
$TTL 300
|
||
@ IN SOA ns1.example.com. admin.example.com. (
|
||
1524952218
|
||
300 ; refresh
|
||
900 ; retry
|
||
1209600 ; expire
|
||
1800 ; ttl
|
||
)
|
||
|
||
; Name servers
|
||
IN NS ns1.example.com.
|
||
IN NS ns1.example.com.
|
||
|
||
; A records
|
||
@ IN A 123.123.123.123
|
||
update IN A 123.123.123.123
|
||
dyn IN A 123.123.123.123
|
||
|
||
Don't forget to set your own domain names, name servers and ip addresses Furthermore, add this zone file to your _/var/nsd/etc/nsd.conf_
|
||
|
||
## Configure and Install nsd-dyndns
|
||
|
||
* Download the scripts from here: [https://codeberg.org/mclemens/nsd-dyndns](https://codeberg.org/mclemens/nsd-dyndns)
|
||
* Copy _dyndns.conf-dist_ to _/etc/dyndns.conf_
|
||
* _\# cp dyndns.conf-dist /etc/dyndns.conf_
|
||
* Edit _/etc/dyndns.conf_ to your needs
|
||
* Copy _dyndns.sh_ to _/usr/local/bin/dyndns.sh_
|
||
* _\# cp dyndns.sh /usr/local/bin/dyndns.sh_
|
||
* Make the script executable:
|
||
* _\# chmod u+x /usr/local/bin/dyndns.sh_
|
||
* Add _/usr/local/bin/dyndns.sh_ to your crontab
|
||
|
||
## Configure your router
|
||
|
||
Configure your router to query the following URL:
|
||
|
||
http://update.example.com/update.html?qwertzuiop1234567890
|
||
|
||
Don't forgert to set your own domain name and to replace the string after "?" with the password you configured in the config file.
|
||
|
||
# What it does
|
||
|
||
When your router gets a new IP and therefore sends an HTTP request to your server, a similar entry should appear in your _/var/www/logs/dyndns.log_:
|
||
|
||
update.example.com 123.123.123.123 - - [29/Apr/2018:20:48:19 +0200] "GET /update.html?qwertzuiop1234567890 HTTP/1.1" 200 6
|
||
|
||
When the script is executed e.g. via cron, the following happens:
|
||
|
||
* It greps the last line of _/var/www/logs/dyndns.log_ where the correct password was found and extracts the requesting IP address
|
||
* It checks if this IP is the same than the last time
|
||
* If it's a new IP, then it replaces the forth line in your zone file (the line with the version number) with a new version (current unix time stamp)
|
||
* As a second step, it updates the A record of you DynDNS domain (dyn.example.com in our example)
|
||
* It then stores the new IP in the file _/tmp/last\_dyndns\_ip.txt_
|
||
* Finally it reloads NSD
|