E3000 Dropping Some Clients Randomly - Constantly Resetting

Question

We have an E3000 that we're using in a public spot to allow people to get online.  A variety of client platforms connect, from game stations to PCs/Macs, and portable devices.  Mostly the E3000 does a good job, but there's one problem which is becoming a pain.
At least once or twice a day we get a report that people cannot connect to the internet on their devices.  We ask around, and some can, some cannot.  They're all still connected to the E3000 and showing good signal, it just isn't carrying internet.  The few times I've checked, the devices having problems have a self-assigned IP address, rather than one from the DHCP server on the E3000.  I've seen cases where my iPhone is connected with no problem, but my iPad ,sitting right next to the phone, cannot access web sites.
The only solution we have is to then go back, power down the E3000, power it up, and wait.  That fixes the issue for a short time.
As you might imagine, taking the router up and down all day is getting tiresome, and I know this cannot be right.
One of our volunteers suggested that maybe the difference is the band of the devices.  My phone, for example, uses G, and my iPad N.  I don't see how that could be the problem, though, since they're both still connected to the router...  One just doesn't have a valid IP.  Still, I offer that up for confirmation or to be shot down.
Any help would be much appreciated.  We're on the verge of just replacing this with another box.

Answer 1

  Please note that my previous reply concerned wireless devices only.  Devices that are connected to the Ethernet ports of the router automatically have their MAC address registered which is required for packet routing.  Direct connected devices can get to the internet without using DHCP assistance only if they have been configured with an IP address that does NOT conflict with one dynamically assigned by the DHCP server on the router and is also configured with the router's IP as it's gateway and the correct DNS addresses.  Having come from an IT network environment I am a firm believer of using DHCP unless there are mitigating circumstances.
Also check your router to make sure it is using firmware version 10.0.4 as it contained fixes for it's Guest Network feature.