Ubuntu (Gutsy): DynDNS Client Setup

Hello again, this time we’re going to setup a DynDNS client so your computer/server can be reached from anywhere.

Step 1

First, you need to create an account with DynDNS to do so follow this howto: https://www.dyndns.com/services/dns/dyndns/howto.html.

Step 2

First we’ll install ssh and ssh-socket so we can send our DynDNS user and password encrypted instead clear text:

$ sudo apt-get install ssh libio-socket-ssl-perl

Step 3

Install ddclient:

$ sudo apt-get install ddclient

Step 4

The installation will prompt you some questions. For the first one it ask for your dynamic DNS provider, select http://www.dyndns.com:


Then, put your fully qualified domain name(s):


Now, your DynDNS requistered username and password:



And finally, type “web” as the DynDNS interface to use:


Ok, so long we’ve finished installing ddclient but there’s still more work to do in order to get it working properly.

Step 5

We, need to change the ddclient configuration file (/etc/ddclient.conf) in order to use ssh to send the username and password, and to properly check the IP adrress. From the command line open ddclient configuration:

$ sudo vim /etc/ddclient.conf

In the generated configuration file you’ll probably see something like the following (The parts in italics will be different, the bold parts are going to change so special attention on this):

# Configuration file for ddclient generated by debconf
# /etc/ddclient.conf
use=if, if=web

Step 6
We need to change the configuration so ddclient get our public IP address properly, and to send our username and password over ssh.

DynDNS has a web interface to get your public IP address, this is equivalent to manually invoking http://checkip.dyndns.com/. But we need to properly configure this interface, so change the line use=if, if=web for the following:

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

Second, add to your configuration file just below the initial comments the following:


The above two lines tells ddclient to use ssl for its connection and to update your public IP address every 5 minutes (specified in secconds).

Step 7

Now, we must make sure that ddclient is set to run as a deamon. Edit /etc/default/ddclient:

$ sudo vim /etc/default/ddclient

And make sure that:

# Configuration for ddclient scripts
# generated from debconf on Tue Jan 29 20:23:32 CST 2008
# /etc/default/ddclient
# Set to "true" if ddclient should be run every time a
# new ppp connection is established. This might be useful,
# if you are using dial-on-demand
# Set to "true" if ddclient should run in daemon mode
# Set the time interval between the updates of the dynamic DNS name in seconds.
# This option only takes effect if the ddclient runs in daemon mode.

Step 8

Finally, restart your ddclient and if no error is printed you’re good to go:

sudo /etc/init.d/ddclient restart

Port Forwarding

In order to deliver services on the net, you must open the corresponding ports for the services that your computer/server will provide, this is called Port Forwarding. Unfortunately this howto does not cover that topic. To do so you can visit http://www.portforward.com/routers.htm, where you can read how to port forwarding for your specific model of modem/router.

Happy hacking!

Ubuntu (Gutsy): DynDNS Client Setup

Linux: Configuring a Server for Static IP

This mini HOWTO explains the required configuration for a static IP.

Before proceed we must know the following configuration of our network:

  1. The IP Address to be used for our server;
  2. Netmask of our network;
  3. Broadcast IP address; and
  4. The gateway IP address.

First, we must open for edit the file /etc/network/interfaces:

$ sudo vim /etc/network/interfaces

Once there, we must find the network interface to be configured from a dynamic IP address to a static one. In this case it will be eth0:

auto eth0
iface eth0 inet dhcp

In the above example we can see that the interface eth0 is configured for dhcp (dynamic address). To change to static IP address configuration we must set the following:

auto eth0
iface eth0 inet static

Finally, we restart networking services:

$ sudo /etc/init.d/networking restart

And that’s it, we’ve now our server configured for static IP address.

Happy Hacking!

Linux: Configuring a Server for Static IP

Configuring 2Wire as a Bridge

This HOWTO helps you to set your 2Wire ADSL modem as a brifge.

I was faced to use a 3com router over 2Wire ADSL modem cause it supports content filtering. We required this functionality to avoid users from browsing freely on the web, but 2Wire modems doesn’t support that functionality. So we’ve set our 2Wire ADSL modem as a bridge and let our 3com router to handle the Internet connection.

This is not the last time that we’ll tell you: WARNING!!! This is and advance topic and we assume that you know what you’re doing.

Step 1

To set our 2wire modem as a bridge first open Firefox (or the browser of your choice) and enter enter the following address: http://gateway.2wire.net (if you can’t access this page try


Once there, click on Broadband Link, located on the top of the page as a tab (the second one).


Step 3

Now click on Advanced Settings from the same menu bar (if a password is requested provide it).

Under the section DSL and ATM:

  1. For the ATM Encapsulation parameter select Bridged LLC option.
  2. And for the ATM PVC Search parameter select the option Disabled.

Under the section Broadband Network:

  1. In the Connection Type parameter select Direct IP (DHCP or Static) option.
  2. And leave blank the Username, Password and Confirm Password textboxes.

Step 4

Enter the following address: http://gateway.2wire.net/mdc or http://gateway.2wire.net/management (or

Once there click on the Configure Services link in the Advanced section from the vertical menu located on the left of your window and disable the option Enable Routing (unchecked) to set your modem as a bridge.


Now check that the Power, Network and ADSL leds on your modem are turned on and green, and your Internet are turned off or orange (depends on the model).

And that’s it. Your 2Wire modem as a bridge!!!!

There’s another way to set your modem as a bridge, but is a trick… quick and dirty. To do so simply go to the Broadband Link options and click on the Advanced Settings from the menu bar (seen on step 3), and type a completely wrong Username and password for your connection (say x for the user and x for the password) and that’s it!

Yeah, quick but too dirty for a formal configuration.

Configuring 2Wire as a Bridge