"-keevill-" <keevillus@yahoo.com> hath wroth:

>I have an office network with 5 wireless access point /routers giving access
>to all areas of the office. They are connected via LAN cable to the central
>switch. I have configured each one with DHCP with ranges which do not
>overlap each other.

Bad idea.

>I am told that this is a bad idea and that I should just
>configure one of them as a DHCP server and disable the others for this.

I think I was the one that suggested you do that. I'm too lazy to
lookup the previous thread and supply a reference.

>If I do that , then only machines which are within range of the wireless
>router config for DHCP can connect. Others, Since they can't reach the one
>config for DHSP they cannot get IP addresses.
>Is this normal?

Nope. That's not normal. It should work. I have several systems,
including my palatial office, setup that way. However, I don't recall
the details. Where you can go wrong is:
1. If you have all your access points or routers setup as routers.
That won't work as the DHCP broadcast has to go from the LAN->WAN
interface.
2. If your unspecified hardware has a problem passing broadcasts to
or from the LAN to the wireless interfaces. Note that DCHP is done
with broadcasts and do not require an IP address to function.
3. You have some device between the access point LAN ports that you
didn't mention (such as an overly smart managed switch, VLAN, VPN, or
router).

>How should I proceed please?
>I prefer not to give fixed IP to all machines - about 50 .

Easy. Download a DHCP/BOOTP query tool:
<http://www.weirdsolutions.com/weirdSolutions/files/products/desktopSoftware/desktopQueryTool/querytool_free.exe>
Fire it up on your LAN/WLAN and see if it can find a DHCP server. Type
anything you want into the "device identifier" field. No need to
assign an IP address. In fact, you can intentionally assign a totally
wrong IP address to the client and it should still work as it's all
running on the MAC layer. I just tried it with my static IP assigned
workstation and it works fine. Here's the results:
option PKT:Opcode=2
option PKT:HType=1
option PKT:HLen=2
option PKT:Hops=0
option DHCP message type=5
option PKT:Flags=32768
option PKT:Seconds=0
option PKT:XID=41
option PKT:SName=
option PKT:Boot file=
option PKT:CIAddr=0.0.0.0
option PKT:YIAddr=192.168.1.100
option PKT:SIAddr=192.168.1.1
option PKT:GIAddr=0.0.0.0
option PKT:Magic cookie=99.130.83.99
option Subnet mask=255.255.255.0
option Gateways=192.168.1.1
option Domain name servers=192.168.1.1
option Broadcast address=192.168.1.255
option Server identifier=192.168.1.1
option DHCP address lease time=7200
option DHCP renewal time=3600
option DHCP rebinding time=6300
option PKT:CHAddr=00-00

The test to run is very simple. Try the DHCP query first from locally
connected via CAT5 laptop. First try plugging it into the unspecified
device acting as a router and DHCP server. That should work and give
you a clue as to what to expect. Next, plug in to one of the routers
you have setup as an access point (with DHCP server disabled). That
should also work. Note that we have done NOTHING that involves
wireless at this time. Try it with your other access points. If the
access point does not have a built in ethernet switch, borrow a cheapo
ethernet switch, and install it between the backhaul cable and the
access point.

One you have determined that it works via the wired CAT5 network, try
it via wireless. There's a real possibility that it will not work
because of problems passing broadcasts between wired and wireless.
Look for settings such as "AP isolation" or "client isolation" that
will cause such problems. If you experience this problem, please
disclose the exact hardware, hardware version, firmware version of the
access point so I can raise hell with the manufactory.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558