Inherited ISP host configuration nightmare
GG> [...] DNS was misconfigured from the start,
GG> causing dial-up clients to use a SMTP/POP3 hostname of
GG> "domain.com" instead of "mail.domain.com". We need
GG> "domain.com" to resolve to the NT web server for
GG> "http://domain.com" requests and to the Linux mail server for
GG> mail client software. [...]
No problem, (I alluded to this yesterday). Just run a web server on
the linux machine and have it issue HTTP redirects from domain.com
to www.domain.com. You could also port-forward, but I think the
redirect is easier to get right (and less disruptive as you are getting
it right). Apache would do just fine.
The bigger picture: Maybe you want to bring in an experienced
firefighter for while, learn from him and then take over? Good bosses
usually like 'this is new, I'll need to learn' almost as much as they
like 'sure, I can do it.' Yours in particular should by now.