An Internal to External mail bridge configuration

[WannabeLinuxAdmin]

Hi All,

I am trying to setup a mail server. I am using CentOS 4, running sendmail, dovecot and (eventually) fetchmail.

The system is for a small group of users who need to be able to email customers from there terminals. They have a hosting package with BT giving them 100 mailboxes (name@foobar.com etc) which I am checking with fetchmail, each accounts mail sent to the internal users mail account:

bob.smith@foobar.com on BT's server -> fetchmail deliver to local user "bob.smith" -> dovecot -> Mozilla Thunderbird

Outgoing mail is sent via BT's SMTP server.

I hope that makes sense. OK - to the point

The users are not tech savvy. They know their email addresses (bob.smith@foobar.com etc) and want to email each other. This would mean the email travels throught the local sendmail to BT's SMTP, then to the BT hosted mailbox, to be fetched by fetchmail, and delivered locally. This is very long and tedious. I would like any mail to "@foobar.com" to be delivery directly via my sendmail to the relevant user, and not via BT's smtp. My servers hostname is "master.mynetwork".

Any ideas? Im very new to Sendmail and Im hoping its possible.

Thanks