http://www.lomcn.co.uk/forum/showthread.php?t=8217&highlight=router+guide
or simple
ok, first thing, check if u can forward ports... if u can u can find out on another thread how to do it. ...
If u cant port forward its DMZ time lol .... all explained below as simply as a can make it im afriad.
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1. U need to set-up a DMZ in your router, you do this by going into the router- type 192.168.1.1 in Internet explorer adress bar. Not sure where DMZ option located (depends on make of router) and set the DMZ to 192.168.1.50
2. Go to network connections on your computer, open it, select TCP/IP and click properties, from here you need to setup an static IP address, this is done by clicking th "Specify and IP" check button
3 Put in 192.168.1.50 as the static IP subnet mask will fill itself in. Then u need to go into your router again (see step one) and find all the DNS server info, this also needs to be entered. You do this by clicking the "advanced" button at the bottom of the IP information window where you just specifyed the IP. Click the DNS tab at the top and enter ALL the DNS Information.
4. The nesxt thing to do is to start the server up, using the server launcher programs enter 192.168.1.50 as the IP (this puts the correct IP in all files) and leave the 4 u need to change ready for editing.
5. Now you need to change these four files
5.1 In DBsrv200
Addrtable!
192.168.1.50 xx.xx.xx.xx <---- your NET IP
5.2
Serverinfo!
192.168.1.50 xx.xx.xx.xx 7200 (replace xxx with net IP)
6. Next go into Logsrv
Addrtable!;Server Title Remote Public Gates...
Oblivion Line1-7 192.168.1.50 192.168.1.50 xx.xx.xx.xx:7100 (replace xxx with net IP)
6.2
ServerAddr!
xx.xx.xx.xx <--- Net IP
192.168.1.50
192.168.1.50
192.168.1.50
This is as clear as i can make it and i hope it gets your server online, i KNOW this way works because i am running Oblivion server on this exact setup as we speak
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Credit for this goes to IamDeath --- i just edited it and added a few things for simplicity!
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from atoms post