On Dec 11, 5:14 am, "-keevill-" <keevil...@yahoo.com> wrote:
> "Jeff Liebermann" <je...@cruzio.com> wrote in message
>
> news:r3lpl3d3o96p7604tf4b0bqvj9brpr1pg9@4ax.com...
>
>
>
>
>
> > "-keevill-" <keevil...@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/desktopSo...>
> > 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.
>
> I am sorry to report a total failure of that test. I cannot get any response
> from that test tool no matter whether I use hard wired connection or
> wireless. Connecting my laptop to any of the access points whether they have
> DHCP enabled or not produces a 'no responses received' message from the
> tool.
> I can ping any station on the network from the notebook and an IPCONFIG/all
> shows an ip address 192.168.0.83 which has been given my by the only router
> with DHCP configured. The router IP is correctly shown as 192.168.0.247
> which is also the DG.
> If I move away to another access point on which DCHP has NOT been configured
> to run, then I cannot connect. All this has been done from my notebook.

Interesting as people have said dhcp is a broadcast protocol ? which i
think i swhere the problem is

Do your ap's have an entry for ip helper addresses ?

In Cisco and other routers/acess points (DDWRT for example) you can
set a helper address so that things
like DHCP can work.

can you post the ranges of ip adresses your using for each ap (they
are all in the same network right ?)

of the top of my head you could get a linksys router put ddwrt on it
and use that as a central dhcp server as long as all the access points
where on the same network or you could get a second hand cisco 2500
or 2600 and use that to hand out ip addresses

The second hand cisco route would alow you to have each ap have its
own network if you desired - just set up mutiple ip adresses on the
ethernet port.