Sending external to domain that is also local?

[b4mule]

I have setup a sendmail/fetchmail server (if you can call it that) that takes e-mail from a server external.domain.net. It puts e-mails from several accounts in this external domain into local mail boxes on my server that can be checked by my local users (the LAN has no other connection to the internet, the linux box has 2 network cards, one for the LAN and one to the internet). I maskerade as external.domain.net to keep the internal e-mails from having to go out and come back in.

My problem is that not eveyone that has an account at external.domain.net wants to use the LAN to check there e-mail (a select few have internet access and not a connection to the LAN), and insted use there internet access to send/recieve there mail directly from external.domain.net.

Because of this they dont have accounts on my linux server and there mail stays on external.domain.net but when someone tries to send one of these peoplean e-mail from the LAN my e-mail server resolves external.domain.net as itself but cant find the username and gives up.

So after the long.... the short of it is.... is there a way I can force these e-mails out into the big wide world?

Any ideas would be most greatful as I am really stuck on what to do about this one?!?!

 

[jad]

umm ... easiest way is to make them all use your mail server. however you could get them accounts at a different address on the net (eg. free.pop3.com) for them to receive mail from (even though they send via external.domain.net, and alias those specific peoples email to free.pop3.com?

user1 <-- internal user
user2 <-- net user
user3 <-- ANother internal user

user2 is given account freeuser8946@free.pop3.com ...
user2@external.domain.net is aliased to freeuser8946@free.pop3.com in /etc/mail/aliases, and newaliases is run.
user2 picks up email from free.pop3.com, and sends to external.domain.net

user1 emails user2 and user3

user1's email gets delivered to localhost for user3, and freeuser8946@free.pop3.com
user2 picks up mail from freeuser8946@free.pop3.com and replies to external.domain.net
your PC picks up the mail from external.domain.net (with fetchmail) and gives it to user1.

well it sort of works