gethostby* users

[Les Mikesell]

Andy Green wrote:

>> But, if anything else currently has
>> the ability to manage customizable helper processes and multiplex jobs
>> efficiently among them in a way that only requires mime and zip
>> unpacking to be done onces even if you scan multiple times, I'd be happy
>> to hear about it.
> 
> ''Postfix before-queue Milter support
> 
> Introduction
> 
>  Postfix version 2.3 introduces support for the Sendmail version 8
> Milter (mail filter) protocol. This protocol is used by applications
> that run outside the MTA to inspect SMTP events (CONNECT, DISCONNECT),
> SMTP commands (HELO, MAIL FROM, etc.) as well as mail content. All this
> happens before mail is queued.
> 
>  The reason for adding Milter support to Postfix is that there exists a
> large collection of applications, not only to block unwanted mail, but
> also to verify authenticity (examples: Domain keys identified mail,
> SenderID+SPF and Domain keys) or to digitally sign mail (examples:
> Domain keys identified mail, Domain keys). Having yet another
> Postfix-specific version of all that software is a poor use of human and
> system resources.
> 
>  Postfix version 2.4 implements all the requests of Sendmail version 8
> Milter protocols up to version 4, including message body replacement
> (body replacement is not available with Postfix version 2.3). See,
> however, the workarounds and limitations sections at the end of this
> document.

I suspect those limitations include not passing info about 
authentication and encryption the same way as sendmail, and that would 
keep it from working out-of-the-box with MimeDefang.  At least I'm not 
aware of anyone making it work yet.  If I had a problem with sendmail 
I'd probably put some effort into that.

> I have been able to get Postfix to do what I want without too much of a
> massive effort, whereas when I first tried to use Sendmail I though the
> m4 config must be an April Fool's joke.  I guess if mail is a large part
> of what you do, you can ride over that kind of quirk and become and
> "sendmail expert" and get the job done.

The basic part of sendmail configuration has been solved by including 
the m4 macros for all the common situations that are invoked by a 
one-line entry in sendmail.mc. As shipped in fedora, changes to 
sendmail.mc will automatically rebuild sendmail.cf and take effect 
whenever sendmail is restarted.  And other than needing one change to 
accept outside mail, the stock config shipped with fedora is good for 
most internet situations.  The aliases, access, mailertable, etc. files 
are relatively straightforward to configure for your local situation. 
Using MimeDefang solves the rest of the problem for additional 
customization.  When using it, you can simply write your site-specific 
additions in a perl snippets that execute in the milter phases instead 
of having to mess with the mailer's internal language or limitations. 
Being able to verify recipients on a different machine via smtp before 
accepting a message is a good example of that kind of extension.


-- 
   Les Mikesell
    lesmikesell at gmail.com