> >If you've got more than one server, configure your main mail server to
> deny all SMTP connections from outside your own domain.
>
> This doesn't really work well for an ISP. This also disallows the ISP's
> customers to access their own email from another ISP.
Mail is picked up via POP3 or IMAP generally, not SMTP. If a user wants
to use another ISP for dialup, fine, but they should use that ISP's SMTP
server to send outbound mail.
Brian