On Tue, Feb 01, 2011 at 06:11:58PM +0100, Ignacio Garcia wrote:
> > However, if Perdition presents a unified IMAP interface, you could
> > perhaps use an "rimap" backend with Cyrus SASL to authenticate the
> > user.
> >
> > I am not aware of any SMTP proxies whose downstream SMTP server is
> > selected after user authentication. It is probably easiest to just
> > operate a unified submission server that authenticates the union of the
> > two sets of users, and then routes to the right server via sender-based
> > routing. In other-words, not a proxy but a store-and-forward MSA.
> >
> > Postfix can do that.
>
> Victor, thanks for your quick response.
>
> yes, I did not take into account that authentication does not always
> take place in SMTP.
It does if you require it, as is normal with a submission service.
> So I guess that leaves me with no other option but
> to consider a round robin setup.
No, you can create a unified submission server which accepts submissions
for both environments, and forwards to the right server for outbound
delivery.
> However, I'm not sure how this works.
> Do I need to setup each postfix server to accept messages from/to both
> sets of users, or in this scenario, if the first connection fails, it'll
> try the second automagically?
> Can anybody point me to a tutorail, howto, etc. on how to setup postfix
> in a round robin environment?
You are not thinking very clearly yet. You must distinguish clearly
between:
- Submission, users submitting mail for outgoing delivery. This is
visible to users, since they set the server in question as their
MUAs "SMTP server". This needs its own design, and it is what I
thought you wanted help with.
- Inbound MX service. Just publish appropriate MX records, and add
front-end SMTP servers to each of the two environments as necessary.
In ISP-grade implementations the SMTP inbound servers are not also
IMAP servers, rather they forward mail to IMAP servers (via LMTP
or SMTP).
Which do you need help with? State clear requirements for either or
each problem, and work from there.
--
Viktor.
