Connection Sharing With NTL Freedom Broadband

Hi,

My customer has NTL Freedom ADSL broadband at his home office. While
there was only one user, the 'squashed frog' modem provided by NTL was
connected directly to the USB port on the PC and this worked fine.

It was necessary to share the connection when another employee began
working from this office and we changed the setup. We used the
following:

---NTL Freedom---D-Link DSL 300T Modem---Netgear Router---Clients

The D-Link was configured as a DHCP Server with the internal interface
having a fixed IP address. The Netgear router had fixed IP address on
the internal interface. The external interface was configured as DHCP
client. The Netgear was also configured as DHCP server.

This worked for a while (approx 2 to 3 months) and then the connection
dropped and we were unable to get it working again with the same
setup. We then tried:

---NTL Freedom---D-Link DSL 300T Modem---Cisco 831 Router---Clients

This had a similar configuration to the first setup and again, this
worked for approx 2 or 3 months before exactly the same thing happened
- the connection dropped for no apparent reason, and could not be
re-established.

After a break of about 2 months, this setup is now working again, but
I wonder for how long...Has anyone experienced similar? Can anyone
shed any light on why this might be? Is it anything to do with the
255.255.255.255 (32-bit) subnet mask from NTL?

Thanks in advance...