3com access point and dhcp service

I am installing a 3com office connect access point on to our LAN. I'm a bit
confused as to whether or not to enable to DHCP service on the access point.
Our domain has a Win2K server running a DNS and DHCP. Would the DHCP on the
access point only server the wireless devices, or would it try to also serve
the wired machines and thereby cause a conflict?

When I tried without the DHCP enabled on the access point the wireless
machines didn't receive an IP. I enabled it but gave it a different scope
than the 2K DHCP just to be on the safe side. It works like this, but I
still don't think it's the proper way. Can anybody help out?

"paristotle" <yabbadabba@flintstones.com> wrote:

>I am installing a 3com office connect access point on to our LAN. I'm a bit
>confused as to whether or not to enable to DHCP service on the access point.
>Our domain has a Win2K server running a DNS and DHCP. Would the DHCP on the
>access point only server the wireless devices, or would it try to also serve
>the wired machines and thereby cause a conflict?

Not sure as to why you didn't get an ip address. If the a/p is on a
switch/network that has dhcp you should get an ip address just like if
you plugged into the switch..

>When I tried without the DHCP enabled on the access point the wireless
>machines didn't receive an IP. I enabled it but gave it a different scope
>than the 2K DHCP just to be on the safe side. It works like this, but I
>still don't think it's the proper way. Can anybody help out?
Can't you set the scope so that it's the same but using ip, as from
your switch dhcp 192.168.123.1 to100 and from your a/p 192.168.123.101
to 254 that way all would work and no over lap ip's...
>

"gene martinez" <njkat@eclipse.net> wrote in message
news:431e6897.58023040@news.eclipse.net...
> "paristotle" <yabbadabba@flintstones.com> wrote:
>
>>I am installing a 3com office connect access point on to our LAN. I'm a
>>bit
>>confused as to whether or not to enable to DHCP service on the access
>>point.
>>Our domain has a Win2K server running a DNS and DHCP. Would the DHCP on
>>the
>>access point only server the wireless devices, or would it try to also
>>serve
>>the wired machines and thereby cause a conflict?
>
> Not sure as to why you didn't get an ip address. If the a/p is on a
> switch/network that has dhcp you should get an ip address just like if
> you plugged into the switch..
>
>>When I tried without the DHCP enabled on the access point the wireless
>>machines didn't receive an IP. I enabled it but gave it a different scope
>>than the 2K DHCP just to be on the safe side. It works like this, but I
>>still don't think it's the proper way. Can anybody help out?

> Can't you set the scope so that it's the same but using ip, as from
> your switch dhcp 192.168.123.1 to100 and from your a/p 192.168.123.101
> to 254 that way all would work and no over lap ip's...
>>
This is what I did. I gave each DHCP a different pool of addresses so that
there would be no conflicts. Initially that worked, but as I added the third
laptop I noticed by its' IP address that it had received an address from our
server's DHCP and not from the a/p.

Then I went to look at the client list on the a/p and found that it had
given out addresses to some wired machines. So even though they are giving
out different addresses they are trying to service the same LAN and this
will cause problems.

Windows 2K DHCP is supposed to generate an alert when there is another
unauthorized DHCP on the same LAN, but so far I have not seen it.

> Then I went to look at the client list on the a/p and found that it had
> given out addresses to some wired machines. So even though they are giving
> out different addresses they are trying to service the same LAN and this
> will cause problems.

Why would it cause a problem? If they are both offering the same range
then there shouldn't be an issue unless you want to say why.

The AP DHCP service is operating correctly, it's a DHCP service, it
doesn't need to care whether it's the wired or wireless and because the
AP is just a layer 2 bridge it's very possible as you've seen, that the
wired DHCP server will also service clients.

There really is no benefit to running the access point DHCP service.

> Windows 2K DHCP is supposed to generate an alert when there is another
> unauthorized DHCP on the same LAN, but so far I have not seen it.

Nope, it's only for detecting Windows 2000/2003 DHCP servers which
haven't been authorised in Active Directory.

http://www.serverwatch.com/tutorials...0825_2193001_2

So just stop doing DHCP on the AP.

David.

paristotle wrote:
> "gene martinez" <njkat@eclipse.net> wrote in message
> news:431e6897.58023040@news.eclipse.net...
>
>>"paristotle" <yabbadabba@flintstones.com> wrote:
>>
>>
>>>I am installing a 3com office connect access point on to our LAN. I'm a
>>>bit
>>>confused as to whether or not to enable to DHCP service on the access
>>>point.
>>>Our domain has a Win2K server running a DNS and DHCP. Would the DHCP on
>>>the
>>>access point only server the wireless devices, or would it try to also
>>>serve
>>>the wired machines and thereby cause a conflict?
>>
>>Not sure as to why you didn't get an ip address. If the a/p is on a
>>switch/network that has dhcp you should get an ip address just like if
>>you plugged into the switch..
>>
>>
>>>When I tried without the DHCP enabled on the access point the wireless
>>>machines didn't receive an IP. I enabled it but gave it a different scope
>>>than the 2K DHCP just to be on the safe side. It works like this, but I
>>>still don't think it's the proper way. Can anybody help out?
>
>
>>Can't you set the scope so that it's the same but using ip, as from
>>your switch dhcp 192.168.123.1 to100 and from your a/p 192.168.123.101
>>to 254 that way all would work and no over lap ip's...
>>
> This is what I did. I gave each DHCP a different pool of addresses so that
> there would be no conflicts. Initially that worked, but as I added the third
> laptop I noticed by its' IP address that it had received an address from our
> server's DHCP and not from the a/p.
>
> Then I went to look at the client list on the a/p and found that it had
> given out addresses to some wired machines. So even though they are giving
> out different addresses they are trying to service the same LAN and this
> will cause problems.
>
> Windows 2K DHCP is supposed to generate an alert when there is another
> unauthorized DHCP on the same LAN, but so far I have not seen it.
>
>

This may sound dumb as it seems you know what your doing but just in case:

You are plugging the cat5 from your LAN into the WAN of the AP??
Sorry but have seen it done before.

"David Taylor" <djtaylor@bigfoot.com> wrote in message
news:MPG.1d88a82935a4633f989e06@news.cable.ntlworl d.com...
>> Then I went to look at the client list on the a/p and found that it had
>> given out addresses to some wired machines. So even though they are
>> giving
>> out different addresses they are trying to service the same LAN and this
>> will cause problems.
>
> Why would it cause a problem? If they are both offering the same range
> then there shouldn't be an issue unless you want to say why.
>
> The AP DHCP service is operating correctly, it's a DHCP service, it
> doesn't need to care whether it's the wired or wireless and because the
> AP is just a layer 2 bridge it's very possible as you've seen, that the
> wired DHCP server will also service clients.
>
> There really is no benefit to running the access point DHCP service.
>
>> Windows 2K DHCP is supposed to generate an alert when there is another
>> unauthorized DHCP on the same LAN, but so far I have not seen it.
>
> Nope, it's only for detecting Windows 2000/2003 DHCP servers which
> haven't been authorised in Active Directory.
>
> http://www.serverwatch.com/tutorials...0825_2193001_2
>
> So just stop doing DHCP on the AP.
>
> David.

I agree that doing DHCP on the AP is a bad idea, but initially I had to in
order to get this thing to work. Oddly enough the DHCP option only appears
in the configuration windows when I assign a static IP to the AP. Maybe I'll
let the AP get its' IP from my 2K server. Thanks for all the suggestions.

David Taylor wrote:

>> Then I went to look at the client list on the a/p and found that it had
>> given out addresses to some wired machines. So even though they are
>> giving out different addresses they are trying to service the same LAN
>> and this will cause problems.
>
> Why would it cause a problem? If they are both offering the same range
> then there shouldn't be an issue unless you want to say why.
>
> The AP DHCP service is operating correctly, it's a DHCP service, it
> doesn't need to care whether it's the wired or wireless and because the
> AP is just a layer 2 bridge it's very possible as you've seen, that the
> wired DHCP server will also service clients.
>
> There really is no benefit to running the access point DHCP service.

Exactly what I thought when I was trying this yesterday. Except I could NOT
get the Win server to give me an IP, which made it a little difficult to
find the AP to turn the DHCP back on. In my case it's a WRT54G with
Talisman and I was just testing it with a Win95 machine with internet
connection sharing, so it's possible that the DHCP server under ICS is
simply too crippled to be useful, but it was frustrating, anyway.
--
derek

> I agree that doing DHCP on the AP is a bad idea, but initially I had to in
> order to get this thing to work. Oddly enough the DHCP option only appears

Why would you have to configure to do dhcp to assign a static ip
address? It's quite sensible to only let you make it offer dhcp when it
has a static ip address otherwise it wouldn't know what scope to offer
addresses from.

> in the configuration windows when I assign a static IP to the AP. Maybe I'll
> let the AP get its' IP from my 2K server. Thanks for all the suggestions.

Why not just assign the ap a static address?