Presently, I have router between my modem and my Airport. That configuration had been necessary because there were no ethernet ports on my (old) Graphite Airport.

But now I have a new Airport Express with enough ethernet ports to accommodate my system.

Is there any advantage/disadvantage to keeping the present “modem> router” configuration, or, is it best just to connect the modem directly to the Airport Extreme and remove the router?

I assume your olf airport looked like this ?

If you were using that with a cable modem or other internet source that had only one LAN ethernet jack on it, you'd need some way to get more ethernet ports to use. Usually you'd go with a switch, but if your cable or dsl modem wasn't intended to be generously handing out many ip addresses, (some are set to only give ONE) then yes you would require a router to share the one IP address it gave you with several computers using invalid LAN ip addresses.

If you've replaced it with a newer airport that has enough LAN jacks, then you should be able to just plug the airport WAN jack directly into the modem, and remove the router entirely. (you'll probably need to reboot the modem when you do this) The airport's LAN jacks are tied into the same internal router in the airport and will by default share your one IP address over invalid LAN ip's for both the wired and wireless clients.

Exactly! And it still works. Well, such that it ever did.

I'll have ready access to my wifes's machine this evening and I'll try the router-free configuration then.

And a special thanks for the restart tip. I might have forgotten that.

Alas, I tried the router-free configuration last night and no joy.

I suspect something was not cabled correctly. I'll give it a go in the next day or two. Perhaps then I'll enjoy success.

It sounds like you probably(/maybe?) need to tell the AirPort to get out of "bridging" mode and start acting like a router. (open up AirPort Utility.app and check the config... i forget which "page" it's on).

In Airport Utility

• Under the Airport icon choose the Wireless tab and set the Wireless mode to "Create a Wireless Network"
• Under the Internet icon click on Internet Connection and for "Connection Sharing" chooose "Share a Public IP address".
• Under the "DHCP" tab set the beginning and ending range of IP addresses to be assigned to devices connecting through the Airport Express

Thanks HI & joemike.

Maybe tomorrow I'll give your (pl) suggestion a go. But for now I am recovering from a 95 minute call to an Apple tech who totally hosed my Extreme and Express. After upteen guesses "…oh well, let's try this…", I finally asked if we could just return the system to its earlier operational state. One would think I was asking for a release copy of Lion. But finally, all was put back to the original configuration. (I'm still using the router).

I don't know who will be using my Express (once I have created a Guest account) so how does one determine the "beginning and ending range of IP addresses that will be connecting to the Airport Express"?

FWIW, I attribute much of my grief to the first step directed by the Apple tech: "Use a paperclip to reset the Extreme base station."

Does that make sense?

normally you would use something like 192.168.0.0 to 192.168.0.255 or 10.0.1.0 to 10.0.1.255 with a subnet mask of 255.255.255.0
Resetting an Airport base station back to the factory default as the tech suggested is always a good place to start when you are having configuration problems. I do it all the time.

It's an excellent place to start, and had I remembered that I probably would not have bought the new AirPort Express Base Station I recently bought.

In the main, I take no issue with resetting the Extreme, but would not the preferable/easier solution have been have been to edit the settings, much as HI and joemike suggested?

Also, were one to edit the settings rather than resetting the Extreme, then in worst case, he could revert to a backup. At least I think that should be the first approach, no?

I wasn't at all clear, there, Harv.

I was not suggesting that you reset, merely lamenting my own failure to have thought of doing so.

Personally I always try changing the setup if I can, but sometimes there is no substitute for resetting the device. I have had situations where Airport Utility could not even "see" the device until it was reset. In such a case I always manually reconfigure from scratch rather than risk restoring a configuration that may well have caused the problem in the first place.

But that is just me.

FWIW,

While the Apple tech was helping me today, she explained that if there were "issues" with her attempts at resolving my problem, then rather than muck about (my term), she would promptly proceed to an Extreme Reset.

Indeed I was armed to the teeth with my trusty paperclip (and a bit of learning, thanks to you all).

Can a little bit of knowledge be a dangerous thing? Nah!