Your realmlist.wtf
Inside of the World of Warcraft folder, there resides a simple file, named realmlist.wtf. This is the file that controls where your game connects to, to play. This is the file we need to modify to point your game, towards Saurfang.
Usual location for this file is:
C:\Program Files\World of Warcraft
or
C:\users\Public\Documents\Blizzard Entertainment\World of Warcraft
Another way to find it easily, is to right-click the WoW icon on your desktop, and click the bottom option, Properties. Once this dialog is up, there should be a leftmost button entitled Find Target..
Clicking this will bring up your World of Warcraft folder. You can now close the Properties dialog.
Either way you come here, you now have a list of files. One of them is realmlist.wtf. This file might or might not be set to open automatically, if not, you will need to open it with something simple, such as either Notepad or Wordpad.
Once open, it will have but 2 lines.
set realmlist ...
set patchlist ...
What comes after can be ignored for now, because we are going to change both lines. set realmlist... tells your game which server to connect to to play. This one we will set like so..
set realmlist saurfang.servers.tanjiers.org
The second is the patchlist server, or where the game connects to, to get the newest patch. Once your game is patched to 2.4.3, you will want to set this like so..
set patchlist 127.0.0.1
This will tell the game to connect back to itself.. which it can't do, and instantly fails. You could set this to anything, such as google.com, but then you'd have to wait a fraction longer, and time is money, right?
Once your lines are set, like so..
set realmlist saurfang.servers.tanjiers.org
set patchlist 127.0.0.1
Save the file right where it is. Now, load your game by running Wow.exe. If your shortcut on your desktop points to Launcher.exe, now is the time to do something about it, by Right-Dragging Wow.exe to your desktop. For those of you who have never made a shortcut this way, it's a nice hidden feature. Instead of a normal drag with the left mouse button, use the right one. Once you let go, you have a nice little menu, choose Create Shortcut... and one will be automatically created, pointing to Wow.exe, you should delete the other one.
Voila, easy, right?