How to connect to modem setup as bridge through Airport Extreme

airportNetwork

I've recently been assigned a static IP by my ISP provider (Sonic.net). My previous setting was with the modem configured to connect using static IP and the Airport Extreme as a bridge. NAT and DHCP were done at the modem, but I couldn't get WOL (Wake On LAN) to work (an Apple technote specifies that this setup won't).

Now I've set up my modem as a bridge and configured the Airport Extreme to handle everything. I've set it up as a static IP and activated DHCP and NAT. I can connect to the Internet perfectly and everything else (connection-wise) works. Yet to try remote access and WOL.

The only problem is that I can't access the modem's admin panel. This should be at 192.168.1.1, but I can't get to it. I think the Airport Extreme is assuming .1 as its internal address.

Is there any way to access the modem in that setup unless directly linked to it (by Ethernet cable)? Will giving the modem another IP (say .201, out of Airport's DHCP range) work? Can I change the Airport's internal address somehow?

EDIT: I've managed to assign the modem an IP of 192.168.0.1, so it should be in another subnet, but this traceroute shows it hopping out after hitting local router.

Best Answer

The problem isn't just that you have two devices using the same 192.168.1.1 IP address, but also that two network segments are using the same subnet (the first 3 parts of the IP, 192.168.1.x). If you're on the AirPort's LAN at 192.168.1.123 and you try to talk to the modem at 192.168.1.1, the network sees "192.168.1" and recognizes it as local traffic, meaning that it never goes out the WAN port where the modem is.

It's sort of like if I try to mail a letter to "123 Fake St, London". I mean the one in England, but there's a city called London right here in Ontario, so that's where the post office is going to send it.

Anyway, when you made your own subnetwork with NAT, you should have picked a new IP subnet to go with it. The AirPort utility calls this part of the IPv4 DHCP range, even though it affects more than DHCP. It's probably currently set to "192.168.1.100 to 200". Just change the third part to something else, like "192.168.0.100 to 200". This will move your entire LAN to the 192.168.0.x subnet, and the AirPort will take 192.168.0.1 for itself.