Wrt160n v3 - Class B Subnet mask

Question

I'm trying to set my router IP to a class B network (172.16.20.x) but the web UI only shows class A subnet masks.. how do I set my subnet mask to 255.255.0.0?
I need to do this so I can use this wireless router as an access point in an existing network.
Thanks in advance.

Answer 1

You can only set subnet mask 255.255.255.0 or smaller on the WRT. It's a consumer router and designed to be used as router in a consumer environment.
If you only use it as access point your LAN with a larger mask you have to choose the IP address which suits you best for configuration purposes.
You wrote you have a network 172.16.20.* but then you write you have subnet mask 255.255.0.0. What is the case? If you only use 172.16.20.* then you should use subnet mask 255.255.255.0 instead. Otherwise, with 255.255.0.0 your LAN would be 172.16.*.*. What do you really use?
If it's 255.255.0.0 you have to pick an IP address for the WRT which works best with the computer most likely to configure the WRT. For instance, if your computer has the IP address 172.16.20.10 and that's the computer you usually use to configure the WRT then set an IP address 172.16.20.* as LAN IP address and set subnet mask 255.255.255.0. With these settings all computers with IP address 172.16.20.* are able to access the web interface. All computers with other IP address won't be able to access the web interface without changing the IP address first.
But this only affect access to the web interface. Wireless connectivity of wireless clients to the LAN is fully independent from whether a client can access the web interface or not.