Re: sendmail m4 email dnsbl

Grant Taylor via Discussion list for the GNU M4 <[email protected]> Mon, 22 Jun 2020 17:00:24 -0600
Newsgroups gmane.comp.gnu.m4.general
Message-ID <[email protected]>
On 6/22/20 2:50 PM, Marc Roos wrote:
> Indeed, I cannot believe I am the first one in the world that wants to 
> query a dnsbl for an email address with a m4 config.

Quit thinking about the macro 4 (m4) language.

What you're wanting to do is about 1% m4 (if that much) and 99% Sendmail 
(if that little).

> This is already widely used through the use of milters.

Yes.  Through /milters/.

m4 (a language that Sendmail uses to build it's config file, but NOT 
used as part of Sendmail's operation) is decidedly different from 
Sendmail's config file which is decidedly different from milters.  There 
is a relation, but one is a fruit, one is a lump of metal, and one is 
plasma ball.

Milters are a completely separate program that can do just about 
anything they want to as long as they interface with Sendmail and 
Postfix in a very specific way.

Milters inherently do things that Sendmail /can't/ do.  Hence why the 
functionality is in the milter instead of in Sendmail proper.

> Someone most likely already have this,

Maybe.  Maybe not.  Even if they do, the fact that you can't find it, 
the fact that I don't know about it (having used Sendmail for almost 20 
years), and the fact that Claus doesn't know about it (being Sendmail's 
maintainer longer than I've been using it), chances are relatively good 
that what you're asking for doesn't exist or is otherwise unavailable.

> or someone with m4 experience should be able to change an existing 
> ip dns blacklist config quickly.
Nope.  You've gone a bridge too far.

You mean that someone with Sendmail experience should be able to....

m4 is a template engine and it's own language.  People that know m4 
don't necessarily know anything at all about Sendmail.  People that know 
Sendmail don't necessarily know anything about m4.  There are some 
people, like myself, that know some of both.

Could someone that knows Sendmail well enough help you create a custom 
Sendmail configuration that will do what you want?  Quite likely.

Does that custom configuration have anything directly to do with m4?  Nope.

The closest that m4 gets to what you want is that it's used to build the 
Sendmail configuration.  Or rather it's the preferred way to build the 
Sendmail configuration.  It is entirely possible to build and maintain a 
Sendmail configuration without using m4 at all.

Asking the m4 community for help with your Sendmail configuration -- 
particularly about something not related to m4 -- is like asking a baker 
why your car is running rough because the baker happens to be in the 
same shopping center as an auto mechanic.  The baker doesn't know cars. 
The auto mechanic doesn't know baking.

> With no (m4) experience, I will never be able to do this better than 
> someone that does have this experience.

You don't need m4 experience to do what you want to do.

You need to re-configure your Sendmail to do what you want.

It is quite common for people to edit (a copy of) the sendmail.cf 
directly to get it to do what they want.  Only /after/ that is done and 
functioning the way that they want do they start to think about 
expressing their change in the mc configuration files.

Even the mc configuration files are a Sendmail specific dialect that 
happens to use m4 as the underlying template engine.

So, ignore m4 for the time being.

Focus on the cf file.  Get it to do what you want.  Then worry about mc 
syntax.

> And since you are here, I think it was not such a bad idea to try 
> and ask here ;)

I disagree.  You have asked the baker why your car is running rough.

> Just searched for it, could not find it.

I should have said that I replied to your question(s) (thread(s)) in 
comp.mail.sendmail.



-- 
Grant. . . .
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