i think the best way to use it is through bridge mode... that way you dont need any port fowarding..
For configuring bridge mode -
1) Log into web interface of modem
2) Select Lan from left hand side options and disable DHCP server. Click save and reboot the modem from the reboot option. While the modem reboots, assign static IP to ur LAN card. You can do it in win xp by double clicking on the lan icon in the tray the selecting properties > TCP/IP>>Properties...use192.168.1.3 ; put the mask in as 255.255.255.0 and Gateway as 192.168.1.1 ; use the foll DNS - Primary 203.94.243.70 ; secondary 4.2.2.1
3) When the modem comes back online, log in again into the web interface for the next part of the configuration.
4) Click on WAN from the options on left hand side
5) in the WAN setup click the edit button in the row which shows PPPoE enabled
6) ATM/ PVC configuration will pop up, let the settings as they are and click next
7) Now from the options that appear select bridging and change the encapsulation mode to "VC/Mux" click next
8) In the configuration screen that follows, make sure that the "enable bridge service option is
ticked..Give any service name or let it remain as it is. Click next
9)In the WAN setup summary click save.
10) Now the wide area network setup will appear click "save/reboot"..let the modem reboot.
The Bridge mode is ready as far as the modem is concerned
now for the dialer
Goto Network connections in Ctrl panel >> Create a new connection >> connect to the internet >> setup my connection manually >> connect using broadband connection that requires username & password >> Put in the ISP name ie MTNL >> put in ur username and password >> add a shrtcut (will make it easy to find after setting up the connex.)
hope this helps..
also ... you woont get full 256kbps ie 32KB download speeds due to loss in transmission.. 24 is around the average speed most people get on triband... though a lot em also get 27KB(including me)!
cheers!