>> Since everything works with phone modem, I'm thinking of replacing the DSL modem with a 3rd party modem that I can configure.

It's probably your ISP that's locking out port 25 for non-trusted IPs and domains. So the likely result a trip back to the store to return the 3rd party modem.

I have the following setup at home: a permanent 2-channel ISDN connection to my ISP which serves as the gateway for the mail server and for the public websites (static IP'), and a cable-company provided DSL modem as a gateway for the other surfing machines.

So what you need is another gateway, which could be as simple as a RAS dial-up, through which goes the SMTP traffic, and keep the DSL as a gateway for everything else.

All you need for this this is a crossover network cable to connect the DSL modem to whatever other hub or router hardware you may have, and to configure individual machines to use the appropriate gateway. And incidentally, this is far easier to set up (and keep up) than by using a spare PC in a "multi-homing" capacity which is another option that's described in several MSDN KB's.

**--** Steve