I bought my first wireless equipment a couple of days back – A Linksys Wireless-G router model WRT54G. I had selected this model after spending a number of days poring through online reviews of various routers.
The box cost me Rs. 3550 (with bill) in Nehru Place. I immediately started working on how to place it in my network. Finally an hour back, I could figure out the right way to configure it. This was the first time I had this network scenario, and I couldn’t
find any documentation on the net about how to configure it. I tried various configuration combinations and finally hit upon the fairly obvious solution. 
For those who have similar scenario, they can probably find some clues here.
- I use my Linux machine to dialup using my Reliance FWP (Fixed Wireless Phone – a last-mile-wireless PSTN) phone. The Linksys router doesnt support normal PAP based dialup. It only does
PPPOE. So I have to still use my Linux machine to dialup. - My Linux machine needs to have the same network as the rest of my LAN machines, so that they can exchange data over Netbios/SMB/Samba. In any case, having multiple subnets in such a small network is a pain.
- I don’t want the Linksys router to route packets between machines in my LAN itself. No point in such an overhead.
- I want DHCP to give out dynamic IP addresses to wireless clients connecting through the AP.
The following option worked for me:
- I connected all the LAN machines including the Linux machine, totalling three, to the LAN ports on the Linksys router. Since the LAN and Wireless ports are actually on a switch, therefore exchanging data between all these machines dont require the Linksys to route at all.
- I left the Internet port unused.
- I setup a DHCP server on the Linux box to give IPs to wireless clients. Actually I have set all LAN machines to take their addresses from this server too. Just that I am giving them fixed IP addresses based on their MAC addresses from within
dhcpd. This is so that I have the flexibility of
configuring `dhcpd` to send the Linksys IP address instead the day I get my DSL broadband connection (Sigh). Also, if then the DSL line goes down for some reason, I can simply use the Linux machine again to dialup, and configuredhcpdto send the Linux machine IP again. - I also happen to have a local DNS server djbdns running, with script generated hostnames/IP addresses for all machines in the DHCP range.
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- Configuring the Linksys router:
- I left the WAN IP address method at DHCP. This will ensure that no default route exists for the router.
- I gave a local LAN address to the inside port.
- I set a WPA password, and added MAC filtering on top of that to restrict wireless clients.
Yes, you are right. I am using the router just as a regular wireless AP 
. I dont need the routing features … yet.
I felt that the configuration becomes far easier if one keeps the following conceptual diagram of this box in mind.
