How to play Mortal Kombat Trilogy for the PC Online.
This is asked by a lot of people, and the short answer is that you cant.
-DONT STOP READING, IT IS POSSIBLE :D-
The reason for this is becouse MKT network play work through the IPX
protocol, and this is a network protocol that can only be used on a LAN.

However there is a way to work around this, using a program called
Gamers Internet Tunnel, in short, GIT. Git allows you to tunnel the IPX
protocol trough the TCP/IP protocol used on the internet. Basicly what it
douse is connect two pc's and tell MKT that there is a IPX network, then
when MKT sends data, GIT converts it to the TCP/IP protocol, sends it to
the other pc, withs translates it back to IPX and then gives the data to
MKT.

I will try to describe how to do this as detailed as possible, so we can
all enjoy MTK over the internet (maybe even play some tournaments?).
Alright, first of all go to http://www.morpheussoftware.net/git/ and download GIT, start the downloaded
file and it will unpack to C:\Git (default).

Next we need to install the IPX protocol, this is for WinXP, on older
versions of windows you will need to figure out how to install IPX
yourself. Alright, rightclick your Network icon and go to property's
rightclick your connection, and click propperties again, then click
the Install button, and click protcol. Select IPX/somthing and click
ok/install/whatever. IPX Should now be installed.

Now try to run git.exe if it gives you a dll error run the WinPcap install
file, this will install the needed dll's. Now try running git again. You
will notice a new icon apears in your system tray (where your clock is)
right click on it and click configruation.

Allright. In the "Forward witch IPX sockets menu click 0000-FFFF : All
sockets and click the add button, it should now apear in the field
below it. in the host or IP field you must enter the IP of your opponent.
To find your ip, just go to www.whatismyip.com :). Port number should be
the same as your opponent, now for using method, one player must use
TCP listen, and the other must use TCP connect. The person who uses
TCP listen is the host/server and the one who connects is the client.

Once again click add and then click the OK button. You should now get
connected to the other person. Note that de host must have clicked OK
before the client, otherwhise the client cant connect to the host, becouse
the host is not listening yet. Now the host rightclicks the GIT icon again
and selects connection status. It should say something like connection
accepted from xxx.xxx.xxx.xxx

If you are on a LAN and you want to be host, you will need to forward
the port you are using on your router, please refer tothe router's
manual to find out how to do this.

Now you both just start mortal kombat, click start network game, one player
select IPX for direct play, and then one player must select host game, and the
other must select join game.

if you have any questions, just ask them here and i will try to answer them!