hello,
i am having DSL modem/router (say IP 192.168.1.1 mask 255.255.255.0 and gateway as 192.168.1.1 ) which is connectd to the Linksys access point (wifi- router)(ip 192.168.2.2 mask 255.255.255.0 gateway as 192.168.2.1)..my dsl modem has been configured for DHCP and NAT ..again linksys is configured as DHCP and NAT ..with this configuration everything is fine and i am able to browse (linksys get an IP say 192.168.1.2 from dsl modem) the net but whenever i disable the NAT i can reach up to Gateway (LInksys 192.168.2.1 )..means no browsing.
My question is Is double NATing is required ??.. As Nat provides single to many service.which is alredy provided by my dsl modem.
pls advice
thanks

I think it depends on how you connect the Linksys router. If you connect the DSL modem to one of the regular wired switched ports you should be able to disable DHCP & NAT because you will be using the Wireless router as a switch. Doing this you will need to reboot the hosts so that the DSL modem supplies the IP addresses and gateway address. The dsl modem/nat router will then be the gateway device. I am assuming that that the DSL router/modem allows multiple computers to connect to it using NAT.

If you wanted to offer a service to the internet, you could leave it as it is, and connect the computer offering the service to the DSL router instead.

One thing that I'm not certain about is if it is OK if both routers are using the same subnet. This might be a problem with double NAT, but not it you use the Linksys wireless router as a switch. Normally, the WAN input on the wireless router is an internet address while the LAN side uses a private address range. You could easily change the LAN side of the Linksys router to a different network range, such as a 10.0.0.0 network or a 192.168.0.0/24 network if you wanted to use double nat.

Thanks for repply..


One thing that I'm not certain about is if it is OK if both routers are using the same subnet. This might be a problem with double NAT, but not it you use the Linksys wireless router as a switch.

Yes you are right that they can not be on same subnet (with NAT).
That is why i am using 192.168.1.0 for dsl modem/router and 192.168.2.0 for linksys acccces point (with NAT enabled on dsl/access point).

Normally, the WAN input on the wireless router is an internet address while the LAN side uses a private address range.

are you talking about myself ?..(if yes) :
well as the modem is providing the IP to access point so these ips wil be from 192.168.1.0/24 pool (private ip pool).
what you are saying is that access point will get PUBLIC IP from dsl modem ?..and what will happen if i connect 2 pc's to access point ..both will get PUBLIC IP ?..
no i dont think so. actually the WAN input on the wireless router (access point) get an IP address from the subnet provided by the dsl modem and these IP's are private.

Finally what i wanted to know is that .. what is the difference between dhcp and NAT.
(is it like that getting IP/mask/dns/gateway automatically can be done by dhcp and theses IP get translated by NAT)

DHCP will supply the IP address, gateway, & nameserver address to the clients. NAT tracks outbound requests from the hosts so it can translate the return traffic to the original request. You could use dhcp even if you weren't using the internet, and NAT can also handle traffic from hosts you statically configured. They aren't interconnected.