In this guide, I will share with you how to connect & control another mac over the internet with dyndns (dynamic DNS). I will take the assumption that you are using broadband & your braodband modem have dyndns client or function built-in. The modem I use in this guide is ZTE ZXDSL 831.

What do you need:
• Mac OS X with ARD client 2.2 or 3.0
• dyndns.com account (it's free)
• VNC admin software*
• internet connection ofcourse ;)

*VNC admin software:
There's many option avaialble. Ranging from the 1st party Apple Remote Desktop to 3rd party Timbuktu Pro. But all those are license software. And I would like to do it at low budget ;) Freeware is the way to go. And my choice is Chicken of the VNC. Go get a copy now.

Please take note the following guides are for the client side. Which mean the mac that you want to control.

Client side walkthrough:
1)  Makesure you have at lease ARD client 2.2 installed.
2)  Sign-in to your dyndns.com acccount.
3)  Click on "My Services". Under "Host Level Services", click "Add Host Services".
4)  Choose "Add Dynamic DNS Host".
5)  Under "Hostname", simply pick a name you like. Check "Enable Wildcard" &
       click "Add Host". For example, I pick "wei803" with domain "dyndns.org".
       My complete dyndns address is "wei803.dyndns.org".
6)  We are done here, remember the dyndns address you just created.
7)  Log-in to your modem's admin page. For my case with ZTE ZXDSL 831,
       I go to 192.168.1.1 in safari (or any browser).
8)  Once you're in the admin page. Click on "Advace" tab.
9)  Under "NAT", select "Dynamic DNS", select "Enable". Key-in your dyndns.com
       login info & host name here. Click "Apply".
10) If everything are in order, the modem will tell you "update successful" .
11) Next we need to do port forwarding. Let's say your client mac is directly
         connected to the modem with no router or hub in between.
12) While we still in the modem admin page. Under the same "Advance" tab, select
        "Virtual Server".
13) Select "Customized service" and pick a name. I use "VNC01".
14) Protocol: TCP/UDP; External & Internal port: start: 5900, leave "end" blank.
15) Now, very important, input your mac's ip address here. For my case is
        "192.168.1.2". You can varify this by checking System Preferences >
        Networks > Ethernet. The mac ip address should display here.
16) Click "Apply" after you've done. We need to create another "Customize service".
        But this time the External & Internal port is 3283. The rest are same as above.
17) Now you can close the modem admin page and go to your "System Preferences".         Navigate to "Sharing", enable the "Apple Remote Desktop" and click on
       "Access Privileges".
18) In the menu, choose which user account and feature you want to be managed.
        You can also specify a log-in password for the VNC access.
19) Disable the firewall if you have it. Or allow access on port 5900 & 3283.
20) We are done with the client.

Please take note the following guides are for the admin side. Which mean the mac that you will use to control other mac.

Admin side walkthrough:
1)  Launch Chicken of the VNC.
2)  Under "Host", put in the dyndns address. For this case I put "wei803.dyndns.org"
3)  Leave the "Display" as it is. Key in the log-in password of the client mac in
       "Password".
4)  The 3 option below are optional.
5)  Click "Connect" and enjoy!

If you fail or unable to connect, it might due to following issues:
• The client is not online.
• Wrong password.
• The client switch to different user account.
• The client disable the Apple Remote Desktop under Sharing.
• The broadband service you using are blocking your VNC connection.
• The client has a router, base station or hub in between the modem. In this case,
     you need to forward the port 5900 & 3283 from the modem to your router,
     base staion or hub. And from your router, base station or hub to the mac. The ip
     address you should input are the device that connected next. See below.

Does my guide works for you? do let me know