DHCP server in D-Link DSL300T

My DSL-300T ADSL modem is acting rather strangely. It has its DHCP
server running and set up to serve addresses in the 192.168.1.x range,
but the PC NIC is being allocated the public dynamic IP address
straight from the ISP.

IPCONFIG /ALL shows the above, but it also shows that the DHCP server
is at 192.168.1.1 (the configured management address of the modem).
How can this be? It seems to be causing some confusion, as DNS
requests are being sent to 192.168.1.1 and getting an ICMP bounce for
destination unreachable.

Ken Wheatley wrote:

> My DSL-300T ADSL modem is acting rather strangely. It has its DHCP
> server running and set up to serve addresses in the 192.168.1.x range,
> but the PC NIC is being allocated the public dynamic IP address
> straight from the ISP.
>
> IPCONFIG /ALL shows the above, but it also shows that the DHCP server
> is at 192.168.1.1 (the configured management address of the modem).
> How can this be? It seems to be causing some confusion, as DNS
> requests are being sent to 192.168.1.1 and getting an ICMP bounce for
> destination unreachable.

Something to do with uPNP, maybe? Is it on?

Geoff

Geoff Winkless wrote:
> Ken Wheatley wrote:
>
>> My DSL-300T ADSL modem is acting rather strangely. It has its DHCP
>> server running and set up to serve addresses in the 192.168.1.x range,
>> but the PC NIC is being allocated the public dynamic IP address
>> straight from the ISP.
>>
>> IPCONFIG /ALL shows the above, but it also shows that the DHCP server
>> is at 192.168.1.1 (the configured management address of the modem).
>> How can this be? It seems to be causing some confusion, as DNS
>> requests are being sent to 192.168.1.1 and getting an ICMP bounce for
>> destination unreachable.
>
> Something to do with uPNP, maybe? Is it on?
>
> Geoff

(replying to your post, because Demon news swerver is doing strange things...)
The DSL300T is not a NAT'ing router (nor is it a router of any other sort) This
would be perfectly normal behaviour for a non-routing device..

(Although the mind boggles as to why it even offers the option of entering IP
addresses, or even offering anything but DHCP passthrough, unless, of course, it
is a DHCP _client_ and expects your network to allocate it an IP address so that
you can program it)

All that said, if it's anything like the old DSL-504 or 624T, it's DHCP server
probably hangs the device dead.

Jim Howes wrote:

> Geoff Winkless wrote:
>> Something to do with uPNP, maybe? Is it on?

> The DSL300T is not a NAT'ing router (nor is it a router of any other
> sort) This would be perfectly normal behaviour for a non-routing device..

Oh right, sorry - I assumed cos the OP was talking about DHCP servers.

> All that said, if it's anything like the old DSL-504 or 624T, it's DHCP
> server probably hangs the device dead.

Hmm. The DNS caching server certainly does that, but certainly my G604T
has been running a DHCP server for a couple of years with no obvious issues.

Geoff

In message <465c4e06$0$313$(E-Mail Removed)>, Geoff Winkless
wrote:

> Ken Wheatley wrote:
>
>> My DSL-300T ADSL modem is acting rather strangely. It has its DHCP
>> server running and set up to serve addresses in the 192.168.1.x range,
>> but the PC NIC is being allocated the public dynamic IP address
>> straight from the ISP.
>>
>> IPCONFIG /ALL shows the above, but it also shows that the DHCP server
>> is at 192.168.1.1 (the configured management address of the modem).
>> How can this be? It seems to be causing some confusion, as DNS
>> requests are being sent to 192.168.1.1 and getting an ICMP bounce for
>> destination unreachable.
>
> Something to do with uPNP, maybe? Is it on?
>
That's how it's supposed to work if you've got the bridge software in it.
The external IP gets passed on to whatever follows it. I think there's a
version of software that does NAT routeing, I think mine even came with it
before I flashed the newer bridge software into it. The device is useful
when you've already got an ethernet NAT router, as you might have if you
were switching from cable to ADSL.
--
Dave
mail da (E-Mail Removed) (without the space)
http://www.llondel.org
So many gadgets, so little time

On Tue, 29 May 2007 18:10:54 +0100, "Dave {Reply Address in.Sig}"
<noone$$@llondel.org> wrote:

>In message <465c4e06$0$313$(E-Mail Removed)>, Geoff Winkless
>wrote:
>

>>
>That's how it's supposed to work if you've got the bridge software in it.
>The external IP gets passed on to whatever follows it. I think there's a
>version of software that does NAT routeing, I think mine even came with it
>before I flashed the newer bridge software into it. The device is useful
>when you've already got an ethernet NAT router, as you might have if you
>were switching from cable to ADSL.

Thanks to all who responded. This device most certainly does NAT, as
the behaviour I described in the OT is recent. Anyway, I now have a
reply from the vendor. They say it's all Vista's fault, and they have
a fix for their later devices, but not mine.

I smell a rat. Especially as the machine involved is running Windows
Server 2003 ....

Mind you, their suggestion that I run it in bridged mode is probably a
good 'un.

Ken Wheatley wrote:

> Thanks to all who responded. This device most certainly does NAT, as
> the behaviour I described in the OT is recent. Anyway, I now have a
> reply from the vendor. They say it's all Vista's fault, and they have
> a fix for their later devices, but not mine.
>
> I smell a rat. Especially as the machine involved is running Windows
> Server 2003 ....

"It's Vista's fault" is rapidly catching up with "Turn it off and back on"
as the default response from technical support nowadays.

--
<http://ale.cx/> (AIM:troffasky) ((E-Mail Removed))
16:37:46 up 31 days, 18:38, 2 users, load average: 0.10, 0.22, 0.16
09 f9 11 02 9d 74 e3 5b d8 41 56 c5 63 56 88 c0