DDNSHowTo(OpenWrt)

DDNS howto

Contents

1. DDNS howto
   1. About Dynamic DNS (DDNS)
   2. Requirements
   3. Installation
   4. Configuration
   5. Trying it out
   6. Tweaks
      1. dyndns.org
2. Old methods

About Dynamic DNS (DDNS)

The DDNS service comes in handy for establishing connections from computers on the Internet to your network at home. This is especially useful if you want to run server software or SSH on your OpenWrt and only have a dynamic IP.

OpenWrt uses the package ddns-scripts for providing DDNS service.

Requirements

• A recent OpenWrt version. This howto was written for the 'Kamikaze 7.07' and later releases.

• An account with a compatible DDNS service, currently
  • dyndns.org
  • changeip.com
  • zoneedit.com
  • no-ip.com
  • freedns.afraid.org
  • Any other that can update when some URL is accessed. The script's quite versatile.

Installation

Install the ddns-scripts package.

root@OpenWrt:~# opkg install ddns-scripts 

If you like to configure ddns-scripts using the LuCI WebUI also install this package:

root@OpenWrt:~# opkg install luci-app-ddns 

Configuration

The configuration is stored in /etc/config/ddns which contains more thorough documentation.

In order to enable Dynamic DNS you need at least one section, and in that section the "enabled" option must be set to one.

Each section represents an update to a different service. This sections specifies several things:

• service (dyndns.org, etc.)
• domain
• username
• password
• IP source (wan, eth0, web)

Optionally, thse following may be specified:

• option update_url (needed if the service isn't supported by /usr/lib/ddns/services)
• check_interval
• force_interval

Use the "check_interval" to specify how often to check whether an update is necessary, and the "force_interval" option to specify how often to force an update. Specify the units for these values with the "check_unit" and the "force_unit" options. Units can be "days", "hours", "minutes" or "seconds". The default force_unit is hours and the default check_unit is seconds. The default check_interval is 600 seconds, or ten minutes. The default force_interval is 72 hours or 3 days.

config service "myddns"         option enabled          "0"         option service_name     "dyndns.org"         option domain           "mypersonaldomain.dyndns.org"         option username         "myusername"         option password         "mypassword"         option ip_source        "network"         option ip_network       "wan"         option force_interval   "72"         option force_unit       "hours"         option check_interval   "10"         option check_unit       "minutes"         #option ip_source       "interface"         #option ip_interface    "eth0.1"         #option ip_source       "web"         #option ip_url          "http://www.whatismyip.com/automation/n09230945.asp"         #option update_url      "http://[USERNAME]:[PASSWORD]@members.dyndns.org/nic/update?hostname=[DOMAIN]&myip=[IP]" 

A short example for a dyndns.org service to configure via UCI CLI:

root@OpenWrt:~# uci set ddns.myddns.enabled=1 root@OpenWrt:~# uci set ddns.myddns.domain=host.dyndns.org root@OpenWrt:~# uci set ddns.myddns.username= root@OpenWrt:~# uci set ddns.myddns.password= root@OpenWrt:~# uci set ddns.myddns.enabled=1 root@OpenWrt:~# uci commit ddns root@OpenWrt:~# ACTION=ifup INTERFACE=wan /sbin/hotplug-call iface 

Trying it out

The script runs when hotplug events happen or a monitored IP address changes, so initially, you have to start it manually. After setting "enabled" to 1, run the following:

sh . /usr/lib/ddns/dynamic_dns_functions.sh # note the leading period start_daemon_for_all_ddns_sections exit 

You can also simulate a hotplug event to trigger a DDNS update manually:

root@OpenWrt:~# ACTION=ifup INTERFACE=wan /sbin/hotplug-call iface 

Tweaks

dyndns.org

Full API documentation available here: https://www.dyndns.com/developers/specs/syntax.html

To enable wildcard domains (*.foo.dyndns.org) on dyndns.org, replace the line in /usr/lib/ddns/services with this:

"dyndns.org"            "http://[USERNAME]:[PASSWORD]@members.dyndns.org/nic/update?wildcard=ON&hostname=[DOMAIN]&myip=[IP]" 

To retain the wildcard setting on dyndns.org, replace the line in /usr/lib/ddns/services with this:

"dyndns.org"            "http://[USERNAME]:[PASSWORD]@members.dyndns.org/nic/update?wildcard=NOCHG&hostname=[DOMAIN]&myip=[IP]" 

Old methods

DDNS scripts have been a surprisingly complicated part of OpenWrt. There have been many other scripts and packages used.

• ez-ipupdate (no longer maintained?)

• updatedd (no longer maintained?) Supports many other services

• JimWright's White Russian dyndns.org script (probably based off a script mbm posted in the forum)

• exobyte's Kamikaze dyndns.org script (based of JimWright's)

  • ddns-scripts's dyndns.org support was based off this

CategoryHowTo