Dynamic DNS

Dynamic DNS service is provided by dyndns.com (no-ip.org is good as well). ddclient script is called at system startup. This periodically checks what IP address has been assigned to the PPP interface and contacts the Dynamic DNS server to update the DNS entry. Thus the router is always reachable using a domain name even though the WAN IP address may change whenever the PPP session is restarted.

root@voyage:/etc/init.d# ls

README          killprocs              php-fastcgi  ssh
bootlogs        klogd                  pppd-dns     sudo
bootmisc.sh     kmod                   procps       sysklogd
checkfs.sh      live                   radvd        udev
checkroot.sh    live-config            rc           udev-mtab
cron            mountall-bootclean.sh  rc.local     umountfs
ddclient        mountall.sh            rcS          umountnfs.sh
dibbler-client  mountdevsubfs.sh       reboot       umountroot
dnsmasq         mountkernfs.sh         resolvconf   urandom
ebtables        mountnfs-bootclean.sh  rmnologin    voyage-pxe
halt            mountnfs.sh            rpcbind      voyage-sync
hostapd         mountoverflowtmp       rsync        voyage-util
hostname.sh     mtab.sh                sendsigs     watchdog
hwclock.sh      networking             single       wd_keepalive
ifplugd         nocatsplash            skeleton     wide-dhcpv6-client

ddclient gets settings from /etc/ddclient.conf

root@voyage:~# cat /etc/ddclient.conf

daemon=600

# check every 600 seconds

# log update msgs to syslog

syslog=yes

# Mail failed updates to user

mail-failure=lorcan@horrorthon.com

# record PID in file.

pid=/var/run/ddclient.pid

## Detect IP with our CheckIP server

use=web, web=checkip.dyndns.com/, web-skip='IP Address'

## DynDNS username and password here

login=xxxxxx

password=xxxxxx

## Default options

protocol=dyndns2

server=members.dyndns.org

## Dynamic DNS hosts

xxxxxxxx.dyndns-remote.com

To debug dynamic DNS, run ddclient in debug mode

root@voyage:~# ddclient -daemon=0 -noquiet -debug

DEBUG:    proxy  =

DEBUG:    url    = checkip.dyndns.com

DEBUG:    server = checkip.dyndns.com

DEBUG:    get_ip: using web, checkip.dyndns.com reports xx.xx.xx.xx

WARNING:  cannot update xxxxxx.dyndns-remote.com from xx.xx.xx.xx to xx.xx.xx.xx until after Thu Jan  1 00:00:30 1970.

DEBUG:    proxy  =

DEBUG:    url    = myip.dnsomatic.com

DEBUG:    server = myip.dnsomatic.com

DEBUG:    get_ip: using web, myip.dnsomatic.com reports xx.xx.xx.xx

WARNING:  cannot update opendns_network_label from xx.xx.xx.xx to xx.xx.xx.xx until after Thu Jan  1 00:00:30 1970.

It's not working in this case, and the error is related to the system date. What date does it think it is?

root@voyage:~# date

Sat Dec 12 19:05:29 GMT 1914

Not sure what's gone wrong there, but might as well install NTP to keep the system time up to date.

root@voyage:~# apt-get install ntp

Reading package lists... Done

Building dependency tree

Reading state information... Done

The following extra packages will be installed:

  libcap2 libopts25

Suggested packages:

  ntp-doc

The following NEW packages will be installed:

  libcap2 libopts25 ntp

0 upgraded, 3 newly installed, 0 to remove and 112 not upgraded.

Need to get 628 kB of archives.

After this operation, 1448 kB of additional disk space will be used.

Do you want to continue [Y/n]? Y

Get:1 http://cdn.debian.net/debian/ wheezy/main libcap2 i386 1:2.22-1.2 [14.0 kB]

Get:2 http://cdn.debian.net/debian/ wheezy/main libopts25 i386 1:5.12-0.1 [72.2 kB]

Get:3 http://cdn.debian.net/debian/ wheezy/main ntp i386 1:4.2.6.p5+dfsg-2 [542 kB]

Fetched 628 kB in 5s (122 kB/s)

Selecting previously unselected package libcap2:i386.

(Reading database ... 18045 files and directories currently installed.)

Unpacking libcap2:i386 (from .../libcap2_1%3a2.22-1.2_i386.deb) ...

Selecting previously unselected package libopts25.

Unpacking libopts25 (from .../libopts25_1%3a5.12-0.1_i386.deb) ...

Selecting previously unselected package ntp.

Unpacking ntp (from .../ntp_1%3a4.2.6.p5+dfsg-2_i386.deb) ...

Setting up libcap2:i386 (1:2.22-1.2) ...

Setting up libopts25 (1:5.12-0.1) ...

Setting up ntp (1:4.2.6.p5+dfsg-2) ...

[ ok ] Starting NTP server: ntpd.

Check NTP. These timeservers are installed by default.

root@voyage:~# ntpq -p

     remote           refid      st t when poll reach   delay   offset  jitter

==============================================================================

-ns1.ooonet.ru   89.109.251.23    2 u    9   64    1  132.414    1.078   0.737

+service0-eth4.d 195.111.98.17    2 u    7   64    1   79.145   -5.807   0.906

+ntp.goneco.de   129.69.1.153     2 u    5   64    1   66.232   -4.427   1.494

*hosted.by.pcext 193.190.230.66   2 u    3   64    1   46.044   -5.622   0.631

Check the date again

root@voyage:~# date

Wed Jul 17 22:06:58 GMT 2013

Restart ddclient in debug mode again

root@voyage:~# ddclient -daemon=0 -noquiet -debug

DEBUG:    proxy  =

DEBUG:    url    = checkip.dyndns.com

DEBUG:    server = checkip.dyndns.com

DEBUG:    get_ip: using web, checkip.dyndns.com reports xx.xx.xx.xx

DEBUG:    proxy  =

DEBUG:    url    = myip.dnsomatic.com

DEBUG:    server = myip.dnsomatic.com

DEBUG:    get_ip: using web, myip.dnsomatic.com reports xx.xx.xx.xx

DEBUG:

DEBUG:     nic_dyndns2_update -------------------

DEBUG:    proxy  =

DEBUG:    url    = http://members.dyndns.org/nic/update?system=dyndns&hostname=xxxxxx.dyndns-remote.com&myip=86.40.184.26

DEBUG:    server = members.dyndns.org

SUCCESS:  updating xxxxxx.dyndns-remote.com: good: IP address set to xx.xx.xx.xx