[CentOS] Kind of OT: internal imap server

[Feizhou]

Hello Les,

> But you are missing the point that once something has been done
> for sendmail via the included m4 macros, no one else ever has
> to understand it again. You just edit a line in the .mc file
> to activate the feature/option following the comments in the
> file or some documentation and the right thing happens.  As
> shipped in Centos you can do pretty much anything you would
> want a mailer to do by changing a few lines in sendmail.mc.

Actually, what I want to get at is if you need anything beyond the 
rulesets that are provided, you cannot do anything unless you understand 
  sendmail rulesets and that is the same if you need to change something 
too.

> It doesn't make any more sense to talk about the difficulty
> of understanding sendmail.cf than it does to talk about
> source code changes.  It is nice that both are available for
> those who might want to tackle changes at that level but it
> is not necessary for ordinary use.

I guess that is the whole point. Ordinary users will probably have no 
clue how sendmail works and when problems arise, good luck trying to fix 
or get around them. So unless they know how to build other stuff and use 
procmail or maildrop, they are pretty much stuck to system mailboxes.

> 
> Then when you add MimeDefang, you also get the ability to
> add in any other operations you want to happen in parallel
> with the smtp chat and control it all with a bit of perl.

Which makes it no different from your dissing of qmail. qmail provides 
very little that you can do before DATA in the smtp chat and mimedefang 
does not kick in until after SMTP DATA in sendmail and they are 
therefore the same.

> 
>> As for mimedefang, qmail lets you do anything that can be described in 
>> perl, shell, C, python, whatever you fancy in fact and reject at the 
>> smtp level too since you can replace qmail-queue or put a filter before 
>> qmail-queue.
> 
> Another way of saying that is that qmail is so bad you have to
> completely replace components to make it usable at all.

Which is no different from sendmail + mimedefang. You have no idea how 
qmail works so I shall ignore your ignorance on this. sendmail gave you 
milter so that you can get at the headers and message body. DJB's 
multiple program approach to separate the different functions 
automatically provides you the ability to get at what you want by either 
modifying that particular qmail program or by replacing like qpsmtpd or 
by adding another program like qmail-qfilter. For this same reason, 
people don't get any trouble from postfix and qmail with regard to 
security issues and sendmail X following the same design principles says 
a lot.

> 
>> I am sorry, but one can get the functionalily of sendmail sans the 
>> neverending list of security updates and that is on two other mta software.
> 
> Sendmail is probably the most heavily audited code available
> today, and none of the other MTA+addons are as well integrated
> or designed for efficiency as sendmail+MimeDefang with its
> multiplexed pool of backend slaves.  Qpsmtpd is promising but
> the project is still in the process of reinventing things
> MimeDefang has had down for years.
> 

yeah, sendmail is probably the most heavily audited code and people 
still find issues just exim also had/has issues due to their monolithic 
design. Ever wonder why sendmail X is following the footsteps of qmail 
and postfix, two mtas that were written by two security different experts?

Multiplexed pool of backend slave? sendmail + mysql anyone?

Let's see, postfix supports mysql, ldap and postgresql out of the box. 
qmail's design allows people to add mysql/postgresql/ldap support such 
that we have qmail-ldap and qmail-sql. So you can use qmail-ldap or 
qmail-sql instead of doing your own. exim also comes with mysql, ldap 
support out of the box.

methinks it is sendmail that is behind here regarding backend slaves. 
You need to add mysql table support and then you have to write the 
rulesets to be able to use those tables.

Well integrated and designed for efficiency eh? I'd like to see 
benchmarks between sendmail + mimedefang versus postfix + amavisd. In 
fact, I'd like to see sendmail + mimedefang integrated with a mysql 
backend versus postfix + amavisd integrated with a mysql backend. But 
the whole thing would be unfair since postfix does connection pooling to 
its backends while sendmail will probably beat the crap out of its 
backend if it supported any sql database at all.

You can diss all other mtas + their addons all you like Les, but 
sendmail X is following the design principles of qmail and postfix which 
says something.