Why was exim selcted as the default MTA?
... and what are my alternatives?
My apologies for putting a partly user question on a development
list, but I think that the decision to select exim as the default MTA was
made on this list rather than on debian-user. Since the List-Archives
search is currently broken, I have no option but to ask here.
The designer of exim has explicitly stated that exim was designed
with 24x7 connectivity to the internet assumed. Because of that
assumption, people who use exim on dialup machines, or machines having
some other intermittent connection, have to workaround some problems. And
since the number of such machines is growing, I think Debian should
reconsider this decision.
Let me give an example of the problem I am facing. I run a private
network, with an unregistered domain name. I dialup to my ISP and use his
smtp and pop server for mail. If I want to queue up my mail on my local
smtp server which will do a 'smarthost' relay to the ISP smtp server, I
must rewrite my envelope sender header, or my ISP will not accept mail
Rewriting the header is not the problem. The consequences are.
Now, all mail originating from my local network (for which the originator
has been mapped to an external email address) and destined for a local
address are also rewritten. I think I can put in 'if' conditions to check
for this case and get around it. But this still doesnt solve my problem.
Consider the case where a mail is addressed to an external address
as well as local ones. Now a copy of the mail will have to be made, and
only the copy destined for the external world will have to be rewritten.
The exim FAQ covers this and states that what needs to be done is to run
_two_ exim servers. The one handling local deliveries has to do local
deliveries and relay a copy of the mail to the other exim server - which
then rewrites the headers and relays it to the ISP smtp server.
I dont know how other mail servers handle this, but I certainly
hope that they handle things better than exim does. Ceratinly, the
configuration files for exim appear better than the greek I saw in the
configuration files for sendmail. But surely there is something which fits
the bill better than exim?
Disclaimer : I am not an expert in MTA's. All questions are non-rhetorical