Macs can't connect to network at work!

Hopefully you guys can help me out with this issue. I work at a small but very upscale hotel. Windows PCs have no problem at all connecting to our wireless network, but Macs seem to randomly have issues. What happens is the Mac can't acquire an IP address from the router. It says it has a self assigned IP. It shows full bars for the wireless network, and is connected to it, but can't connect to the internet. I have tried manually assigning an IP but have had little luck with that. Sometimes it is able to connect fine, but then randomly stops working. Unplugging the router and plugging it back in works, but also kicks everyone in the building off the internet for a short while, which isn't acceptable. Does anyone have an idea what is going on here? This has been an ongoing issue for years now and it would be great to finally have an answer!

Thanks!

Only thing I can think of...

Is the network encrypted or just open?

If encrypted, is it one of those private networks requiring a login for access like many of the chains use for verification?

Is it using WEP for the encryption? This is an issue with Macs in general. I've seen it over and over again with WEP. If it is, it should be upgraded to WPA. This may limit some folks being able to connect, but I doubt very seriously if you're in an upscale hotel, that you've got anyone carrying their 10 yr old computers with them.

Thanks for the response bobtomay. It is an open network, there is no password to join. It seems like 90% of our guests are using Macs these days, and the phones are ringing constantly with people not being able to connect. Is there any way to reset the connection between the router and the Mac short of actually unplugging the router? I just can't keep knocking people in other rooms off the internet to solve one connectivity problem.

With an unprotected network, my next best guess would just be related to distance from the router and signal strength (or old router?)

Spent the weekend in one of the Marriott chains last weekend and tried to download an Audible book on my iPad. In my room it started off at 17 minutes, then went to 13 hrs, then went to 36 hrs, then to 65 hrs, then disconnected. Tried it several times. Finally went to the lobby and downloaded it in about 20 minutes.

If this is a relatively small multi-level building, moving the router to the top floor instead of the ground floor can help in some cases.

Although I can typically troubleshoot my own networks and "eventually" figure out the issue, I am by no stretch of the imagination a network guy. We've got a couple around here a lot better than I am, maybe one of them will pipe in. Give it awhile and maybe bump it again if you haven't heard anything else by this evening.

But here's a page with several tips on boosting the range of a wifi network - link.

I would agree if the router wasn't in the room with the guest having the problems, and the signal is at full bars. There are multiple routers located throughout the property, since we have cabins and other buildings all on the same network.

It really sounds like you need to get a different router. The protocols used to get an IP address and connect are industry standards. It's not like Macs use some other method.
Some high-end network devices have numerous "unique" settings that tinker with the standards. Mind telling us what brand(s) you have?