RRAS problem? default gateway causes conflicts with Exchange 2000 Server

[Bill]

Hi,

We run Exchange 2000 Server on Windows 2000 Advanced Server and Exhange 2000
and 2002 on Windows 2000 Pro workstations.

The basic problem is this:

Certain computers that are configured to browse the internet through the
RRAS server have problems accessing the email server.

Details:

- The RRAS server and the email server are one and the same. That server has
two network cards, one for the LAN and one for the DSL modem.
- Normally, the workstations are configured to use DHCP and are not issued
default gateways and they have no trouble accessing the email server. A few
workstations are configured to allow browsing the internet and they have
fixed IP addesses. Their default gateway addresses are set to the LAN IP
address of the email / RRAS server.
- Those workstations have trouble accessing the email server. It may be that
they can't access it at all. It may be that access to email is very slow. It
may be that they cannot resolve names from the list of mailboxes available
on the email server. Different workstations exhibit a variety of problems.
- If the default gateway is temporarily removed, access to the email server
becomes normal. Of course, browsing is then disabled.
- If the default gateway is changed to another address, access to the email
server becomes normal. Of course, browsing is then disabled.
- The LAN IP address range is 169.254.x.x. That was set before understanding
the purpose of that range. We will change that only eventually unless it is
the cause of the problem.

It may be a problem with RRAS incorrectly routing traffice for itself out to
the Internet. Can anyone see the problem or suggest where to look?

Thanks,

Bill