How to – Connect Belkin Wireless G Router to Fritz!Box SL Modem

Weeks ago my cousin changed his ISP from Alice-dsl.de to T-Home.de and she asked me to install Internet for her. I do not have much experience with installing Internet but I always think it’s simple with installing and configuring. If it’s so hard, no one can install himself and the ISP must be overloaded with the orders of installing Internet. Therefore I made an appointment and went to her apartment and thought it took me 10 minutes to finish the installation but I was wrong.
As I started to install, I read the letter of T-Home and recognized immediately that it requires so much than normal login data. As usual, when we want to connect to Internet through DSL we just need to enter the username (our phone number) and password (optional) but with T-Home I must enter username, T-online-number, Connection ID, number of joints users,… How can I enter these data in my current modem? It doesn’t support so I suggested my cousin to buy a new modem from T-Home.de and I would come again to install for her.
One week later, she called me and when I came to her apartment, she has a new modem Fritz!Box SL. This modem belongs to my cousin’s friend. He didn’t use it anymore and before sending it, he entered all login data. I tested and it works (I told you before, it must be easy) but my cousin has 2 laptops and she wants both of them must connect to internet through WLAN. But this modem doesn’t support WLAN therefore I must connect her belkin wireless g router to fritz box sl modem so that she can use WLAN as she wants.
There are two ways to accomplish this requirement but I didn’t test the second method. You can test it yourselves.
1. Use Belkin Wirelsess Router as Access Point (Easy, already tested)
– Enter all login data to your Fritz!Box SL Modem
– Connect the WAN port of Belkin router to the LAN port of Fritz!Box
– Turn on feature Access Point of Belkin router

– Finish
2. Connect Router to Router (Advanced, not tested)
– Enter all login data to your Fritz!Box SL Modem.
– Restrict the IP range of Fritz1Box SL Modem from 192.168.21.2 – 192.168.21.40
– Disable DHCP of Belkin router.
– Set WAN access to static IP and enter configuration as following. IP Address 192.168.123.2. Subnet mask 255.255.255.0. Default Gateway 0.0.0.0 (or 192.168.123.1)
– In LAN Settings, set LAN IP to 192.168.21.50 with Subnetmask 255.255.255.255.
– Connect LAN port of Belkin router to LAN port of Fritz!Box SL.

Please note that the IPs I use in this post are for illustrating. They will vary in your case. You must connect your own laptop to the router and modem and use ipconfig command to discover your gateway, access it and edit the configuration. I will insert more images in this post if I come by my cousin and take some snapshot. Hope that you can solve your installation with these instructions.
Some helpful links which I read for this case
http://ezinearticles.com/?Wireless-Networking—-Router-Vs-Access-Point&id=70176
http://www.togaware.com/linux/survivor/Router_Router.html
http://www.diffen.com/difference/LAN_vs_WAN