> On Dec 25, 2017, at 3:31 AM, vonProteus <vonproteus+postfix....@gmail.com>
> wrote:
>
> With one is better and why do you think so?
> I’m going to chose one and would like to know your opinion
Disclaimer: I am a Postfix developer and user, and hang out on the
Exim lists only because I've contributed some DANE-related code to
Exim.
With the above noted, I find the Exim source code a distasteful mess,
and observe in Exim a great deal more bug reports and bug fix activity,
which backs up my sense that the code quality in Exim is lower than in
Postfix.
Most users probably don't care about code quality and don't seem to
mind security patches now and then. What sets Exim apart in terms
of features is that it has a lot more built-in controls. There are
things you can do in Exim directly that would require a policy service,
milter or content filter in Postfix. What sets Postfix apart is that
its built-in features are clean and easier to use and understand.
Postfix is not monolithic, and the combination of master-server plus
queue-manager and delivery agents outperforms Exim on busy servers.
The price of Exim's built-in controls is that the configuration
language is a fragile mess of nested curly brackets. Some care is
required to avoid issues akin to "SQL injection" where literal
external data might get confused with Exim's quoting and list
construction syntax.
Postfix, for example, supports LDAP groups with indirect
members as DN references and dynamic groups via query URIs
via the "special_result_attribute" lookup table property.
This required specialized internal code to present a high
level abstraction to the user. In Exim, you get a raw
LDAP lookup interface, and get to split the result set
yourself, and then do any desired DN recursion. In theory,
this is more flexible, you're in charge. In practice it
can be much harder to get the basics right.
My impression is that Exim is more widely used by individual
users hosting their own domain, while Postfix is more widely
used by small businesses, service providers. There is of course
a great deal of overlap, but I would estimate that Exim has more
MX hosts, and Postfix handles more mail.
If Postfix is sufficient for your needs, you'll find it is easier
to use and more reliable. If you need fancy conditional logic
and want it all built-in, Exim may be more to your liking, but
you've been warned, it is easier to misconfigure, possibly in
ways that compromise security, so be careful.
--
Viktor.
