How to configure a Linux-based SMTP *pure* relay for Exchange?
Presently, I'm using an IIS SMTP inside a Win Serv 2003 Web Edition as a relay to an Exchange server, using the instructions published here:
How To Configure a Remote Domain for an Internet Information Services SMTP Mail Relay Server in Windows Server 2003
My question is: does anyone know how to configure a Linux-based SMTP to replace this IIS SMTP? And what software(s) to use?
The summary of what's needed is quite simple:
* for incoming mails, ie mails from Internet:
no open relay (of course) and only relay mails for a specific domain to specific an IP address (in the intranet)
* for outgoing mails, ie mails from intranet:
only mails from the specific IP address (as stated in the previous point) is allowed to relay (actually, this is very point to make sure the SMTP server doesn't act as open relay)
Well, maybe this is a stupid question and you all would tell me that all Linux-based SMTP servers can already do so. But I just don't know where to find instructions on how to do it.
And if you ask me why I would like to replace it. It's because of the several functionalities that I can't find any way to add to it:
* (most important) I need to implement SPF and I can't find any way to make IIS SMTP check the SPF record
* I want SMTP to refuse mails to inexistent addressees, in order to reduce useless traffic
Thanks in advance