DHCP servers in lan

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



--
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"-keevill-" <keevillus@yahoo.com> wrote in message
news:4759f7df$0$26046$88260bb3@free.teranews.com.. .
>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. 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.
> 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?
> How should I proceed please?
> I prefer not to give fixed IP to all machines - about 50 .
>

Question: Why not setup a central DHCP server (separate from the access
points) for wired and wireless clients? I guess I am curious if you have
any wired clients? If so - how are they getting their addresses? Can you
use the same server you are using for DNS?

> Question: Why not setup a central DHCP server (separate from the access
> points) for wired and wireless clients? I guess I am curious if you have
> any wired clients? If so - how are they getting their addresses? Can you
> use the same server you are using for DNS?

There is only 1 hard wired client- with fixed IP.
DNS is provided via ISP and local wireless clients seem to discover dns
provided they can either connect to DHCP server direct or are given fixed IP
..



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Posted via a free Usenet account from http://www.teranews.com

> DNS is provided via ISP and local wireless clients seem to discover dns
> provided they can either connect to DHCP server direct or are given fixed
IP

Seem to discover? Uh, this isn't something to be vague about.

I'd much rather have centralized DHCP. One added benefit to this is being
able to better diagnose networking problems using DHCP leases. The machines
boot themselves as DHCP but get the same IP address every time. This way if
a device is acting up it should be easy to find via logs and such. That and
you can easily see any new devices as they'll show up as new leases, not
reservations.

There's another point to consider, if you've got fifty machines then you've
got the chance that all routers may, at some point, have to issue leases to
every one of them. Just how large are the subnets?

Feh, the headaches of managing multiple routers aren't worth it. Turn it
off on them and use a centralized one with leases instead.

"Bill Kearney" <wkearney-99@hot-mail-com> wrote in message
news:xcadnT81GPk9IMfanZ2dnUVZ_ruqnZ2d@speakeasy.ne t...
>> DNS is provided via ISP and local wireless clients seem to discover dns
>> provided they can either connect to DHCP server direct or are given fixed
> IP
>
> Seem to discover? Uh, this isn't something to be vague about.
>
> I'd much rather have centralized DHCP. One added benefit to this is being
> able to better diagnose networking problems using DHCP leases. The
> machines
> boot themselves as DHCP but get the same IP address every time. This way
> if
> a device is acting up it should be easy to find via logs and such. That
> and
> you can easily see any new devices as they'll show up as new leases, not
> reservations.
>
> There's another point to consider, if you've got fifty machines then
> you've
> got the chance that all routers may, at some point, have to issue leases
> to
> every one of them. Just how large are the subnets?
>
> Feh, the headaches of managing multiple routers aren't worth it. Turn it
> off on them and use a centralized one with leases instead.

Thank you but that is what I am trying to do . If you re-read my earlier
post, I indicate that the client pc's cannot obtain an IP other than ones
which are near the only router rigged up for DHCP.
Or is there something I must do to enable discovery of the DHCP server for
client machines ?



--
Posted via a free Usenet account from http://www.teranews.com

"Bill Kearney" <wkearney-99@hot-mail-com> wrote in message
news:xcadnT81GPk9IMfanZ2dnUVZ_ruqnZ2d@speakeasy.ne t...
>> DNS is provided via ISP and local wireless clients seem to discover dns
>> provided they can either connect to DHCP server direct or are given fixed
> IP
>
> Seem to discover? Uh, this isn't something to be vague about.
>
> I'd much rather have centralized DHCP. One added benefit to this is being
> able to better diagnose networking problems using DHCP leases. The
> machines
> boot themselves as DHCP but get the same IP address every time. This way
> if
> a device is acting up it should be easy to find via logs and such. That
> and
> you can easily see any new devices as they'll show up as new leases, not
> reservations.
>
> There's another point to consider, if you've got fifty machines then
> you've
> got the chance that all routers may, at some point, have to issue leases
> to
> every one of them. Just how large are the subnets?
>
> Feh, the headaches of managing multiple routers aren't worth it. Turn it
> off on them and use a centralized one with leases instead.


Thank you but that is what I am trying to do . If you re-read my earlier
post, I indicate that the client pc's cannot obtain an IP other than ones
which are near the only router rigged up for DHCP.
Or is there something I must do to enable discovery of the DHCP server for
client machines ?



--
Posted via a free Usenet account from http://www.teranews.com

"-keevill-" <keevillus@yahoo.com> wrote in message
> Thank you but that is what I am trying to do . If you re-read my earlier
> post, I indicate that the client pc's cannot obtain an IP other than ones
> which are near the only router rigged up for DHCP.
> Or is there something I must do to enable discovery of the DHCP server for
> client machines ?

Are all the AP's actually AP's or are they wireless routers acting as AP's?
The latter is fine but you have to plug into a LAN port not it's WAN port.
(sorry if you know this but something doesn't sound right)
Also are all AP's using the same SSID and encryption info? The only thing
that should be different about each AP is the IP address and wireless
channel (make sure they are not all on the same channel.)

Your network should look like this

Internet Modem to WAN of Internet Router/AP1 with DHCP enabled, from it's
LAN port 1-4 (if applicable) to each of the 4 other AP's setup with static
addresses outside of the DHCP range of Router/AP1.
With this setup all wireless devices that associate with any of the AP's
will receive a DHCP lease from the internet router and all non lan traffic
with be routed to the internet via it's default gateway.

I would setup like this
router/AP - 192.168.1.254, DHCP 192.168.1.100-199
AP1-4 - 192.169.1.201-204.

Adair

"Adair Winter" <adairw@swbell.net> wrote in message
news:Td37j.6860$AR7.1285@nlpi070.nbdc.sbc.com...
> "-keevill-" <keevillus@yahoo.com> wrote in message
>> Thank you but that is what I am trying to do . If you re-read my earlier
>> post, I indicate that the client pc's cannot obtain an IP other than ones
>> which are near the only router rigged up for DHCP.
>> Or is there something I must do to enable discovery of the DHCP server
>> for client machines ?
>
> Are all the AP's actually AP's or are they wireless routers acting as
> AP's? The latter is fine but you have to plug into a LAN port not it's WAN
> port. (sorry if you know this but something doesn't sound right)
> Also are all AP's using the same SSID and encryption info? The only thing
> that should be different about each AP is the IP address and wireless
> channel (make sure they are not all on the same channel.)
>
> Your network should look like this
>
> Internet Modem to WAN of Internet Router/AP1 with DHCP enabled, from it's
> LAN port 1-4 (if applicable) to each of the 4 other AP's setup with static
> addresses outside of the DHCP range of Router/AP1.
> With this setup all wireless devices that associate with any of the AP's
> will receive a DHCP lease from the internet router and all non lan traffic
> with be routed to the internet via it's default gateway.
>
> I would setup like this
> router/AP - 192.168.1.254, DHCP 192.168.1.100-199
> AP1-4 - 192.169.1.201-204.

Something may be wrong here... I Have all the routers set up with different
SSID. Something like AccessPoint1... APKichen..APAccounts etc... they are
all using NO encryption till I get it working correctly. Some of them are
using CH6 and some CH11. About half each.
Does the SSID hold a clue here ?




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"-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

Jeff Liebermann <jeffl@cruzio.com> hath wroth:

>Easy. Download a DHCP/BOOTP query tool:
><http://www.weirdsolutions.com/weirdSolutions/files/products/desktopSoftware/desktopQueryTool/querytool_free.exe>

A bit more on using the above DHCP query tool:

1. Do NOT check the box for "use BOOTP protocol".

2. Windoze, in its infinite wisdom, caches DHCP requests. You can
sorta tell by how long it takes to return results. If it takes about
2-3 seconds, it's a new lookup. If it responds instantly, then it's
coming from the local cache.

3. I couldn't figure out how to clear the DHCP cache, so I found it
easier to just convince the lookup tool to do a new lookup. To do
that:
- Punch the "Reset" button to clear the display
- Change the "Device Identifier" to something unique.
If you watch the "your address" box, it will return a different IP
address (at least it does that with my static IP system).

--
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

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:r3lpl3d3o96p7604tf4b0bqvj9brpr1pg9@4ax.com...
> "-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

very detailed course of action Jeff - I will attempt this tomorrow when I am
in office and post back.
You did not say if the SSID naming of all the routers should be the same or
different.Mine are all different as I say.
The hardware is all SMC with one Belkin thrown in. 4 are modem / routers
(with modem function not used of course) and the belkin is a router only.



--
Posted via a free Usenet account from http://www.teranews.com

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

>very detailed course of action Jeff - I will attempt this tomorrow when I am
>in office and post back.

Thanks. I'm rather interested in the results.

>You did not say if the SSID naming of all the routers should be the same or
>different.Mine are all different as I say.

It's easier to have them all different for testing. However, it
really doesn't matter for testing DHCP. With different SSID's, you
can control which access point you connect with. With all the same
SSID's, seamless roaming is easier. My experience is that if the
manufacturer does not advertise roaming abilities, it's not going to
work.

>The hardware is all SMC with one Belkin thrown in. 4 are modem / routers
>(with modem function not used of course) and the belkin is a router only.

Ummmm.... model numbers, hardware versions, and firmware versions?
Take inventory.


--
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

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:r3lpl3d3o96p7604tf4b0bqvj9brpr1pg9@4ax.com...
> "-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.
>


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.





--
Posted via a free Usenet account from http://www.teranews.com

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

>> 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.

>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.

Weird. It has always worked on everything I've tried except for a
Windoze Server 2003 with all the sandbox security features enabled. It
also doesn't work with DHCP AUTH (RFC-3118).

I did some tinkering and produced "No response received" if I
unchecked the "Request Broacast Response" box. Please check this box.
Also, uncheck the "Use BOOTP protocol" box.

>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.

Sounds correct. If you can get a DHCP assigned IP address, the query
tool should work. There's no way you can get a valid DHCP assigned IP
address and also not have the query tool work. They go together. Does
your router have a logging feature, which might show some errors?
Syslog?

Did you do the aformentioned failed test via wired or wireless?

Can I presume that the DHCP server is your unspecified model Belkin
router? Could you disclose the model number and firmware version?
Also the SMC access points.

>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.

I don't know what to tell you. This may be an indication of why using
a single DHCP server wasn't working for you. It *SHOULD* work, but
apparently doesn't. Do you have a home system or another router
available for tinkering? If so, then plug your computer into the
router and try the DHCP query tool again.

However, that doesn't really solve the original problem. If the query
tool doesn't work on your LAN/WLAN, then DHCP is not going to work
through multiple bridges (access points).

At this point, I usually drag out the protocol analyzer (Wireshark or
Ethereal), sniff the traffic, spend an hour decoding the junk, but
usually can identify the problem. If you feel ambitious, download
Wireshark:
<http://www.wireshark.org>
and sniff some exchanges (using ipconfig /renew to initiate the
exchange). Compare with what the query tool does. I should mention
that if you've never done this before, there's going to be a rather
major learning curve.

Methinks we're onto the cause of the problem. I guess(tm) is that
it's pointing to the unspecified model Belkin router, if that's the
DHCP server.


--
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

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.

"Neuromancer" <maurice@hauntingthunder.demon.co.uk> wrote in message
news:7e26b295-c2c8-4ee4-a162-88290ece0c9e@b40g2000prf.googlegroups.com...
> 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.





currently I have disabled DHCP on all but the unit which connects directly
to the ISP - a non-wireless SMC7901bra ADSL modem / router and 1 other
router - SMC2904WBRA2 .
The former runs on the range 192.168.0.100-199 and the latter
192.168.0.81-99.
Only wireless client pcs which are within range of the device which has the
DHCP enabled can connect to the network. Other machines I must give fixed IP
when they connect to routers in their range where DHCP is not enabled.



--
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