Possible DNS issue with connection of wireless clients to functionalwired network?

Hi,

I often use google groups for reference when I am stuck with something
technical, but I am now REALLY stuck, and would be grateful for any
help offered.

Historically, I have had no real problems with the setup below - the
occasional glitch, but has worked well.

Had a new laptop from school recently - HP 6715b. It would not talk to
my home network for love nor money. I tried changing drivers, updating
bios, turning on/off lan/wan switching, enabling and disabling the
device. It would happily talk to the school network. I resolved this
issue with an online chat with HP, and then updating my home
networking bits.....

However, in doing so, I have done something 'odd':

The situation is now:

Wired clients, connecting to the router or the switch attached to it
are fine work a treat - DHCP and DNS. I can broswe etc quite happily.

As soon as a wireless client is introduced, connected by the access
point, they connect to the AP fine, and pick up an IP address from the
router no problem.

As they connect, they kill off all external access to websites, both
as urls and as IPs. This disconnects all wired clients too. This
suggests a DNS issue.

All clients, wireless or wired, connect internally to the router,
access point, and network laser printer quite happily, and connect to
each other, via name or IP.

If the wan connection is released and renewed, and the router is re-
started, all clients including the wireless can brwse quite happily,
until a new wireless client is introduced.

It is not limited to laptops - a PDA and a PSP have the same impact,
so I don't think it is a driver/microsoft issue - all pick up IPs
quite happily, but then experience DNS issues, until the router is re-
started.

The hardware involved is:

NTL-1000 cable modem, which is on DHCP to NTL.

Safecom (Securecom) SBRU 10100, which picks up it's WAN address from
the NTL router, and is a DHCP server to the LAN. It was upgraded to
firmware 03.00.00.10.

A D-Link DES 1008-D switch, to feed wired clients, connected to the
router.

A US Robotics USR 5450 Access Point, connected to the router. It was
upgraded to firmware 1.53.

An HP2600n pritner, connected to the router, with a static IP address
outside of the DHCP scope.

A PC which is running internet connection sharing to allow a laptop to
connect next to it via a cross-wired ethernet cable. It has two NICs
to act as a bridge, and works fine.

I have tried various combinations of static and dynamic addresses for
the LAN side of the Access Point.

The access point has had static and dynamic addresses from the router
- the statics were outside the DHCP scope.

I have tried entering NTL's DNS values into the wireless clients,
giving them static and dynamic IPs.

I have tried many settings for the router and access point, including
DHCP proxy on the router, both on and off, turning on and off wireless
privacy, to avoid loop-backs.

All IPs are within the same subnet mask - class C, and there are no
clashing static or dynamic IPs (AFAIK)

Any help anyone could provide would be gratefully recieved.

In terms of knowledge level, I have managed school networks for a
decade, but this particular issue is getting to me - I hope (or not!)
I am missing something simple.

If I have posted this to the wrong group, I would be grateful if you
could point me to a different one.

I have, as usual, searched the groups, but can't find this issue - if
there is another thread that deals with it I'd be grateful for a link
to it.

Kind Regards,

Ray.

An appendage, I have powered the devices in the right order, and have
flushed and reset the DNS on the laptops (not sure how to do this on
the PDA or PSP), as these are the main results from the groups and web
searches I have done.

Kind Regards,

Ray.

If it helps by way of diagnosis, I swapped the DHCP functions to the
USR Access Point, and disabled them on the router - made no
difference, which still leads me to a DNS lookup issue, but not sure
how to resolve.

Kind Regards,

Ray.