Problem with Telecom-brand D-Link 504G routers

[Simon Garner]

I was helping to install Internet connectivity into a cafe last week via
six DSL connections and a Linux box. For some reason they had purchased
six Telecom Xtra-branded self-install starter packs to get the modems
needed. We encountered a problem with these D-Link DSL-504G routers and
I thought I would post the solution here in case anybody else comes
across this in the future.

The problem was that as soon as we plugged more than one of the modems
into the network, it would knock out the others. A bit of head
scratching later, we discovered all the modems had identical MAC
addresses.

These modems have Telecom Xtra custom firmware installed, so that users
see an Xtra-branded control panel when loading up the web interface.
Obviously what has happened is when these modems have been loaded with
Telecom's custom firmware it has also overwritten the MAC address, so
that every one of these modems has the same address. Get more than one
on a network and things go haywire.

After talking to the D-Link helpdesk and being passed through to D-Link
Australia they were most helpful and advised us as to the solution,
which is to telnet into the modem and run the command "do serialize
<macaddress>" to change the MAC address (naturally this command is not
mentioned anywhere in the interface or documentation). The correct MAC
address to use for each modem is printed along with its serial number on
a barcode label on the side of the device.

-Simon