On Fri, Oct 15, 2021 at 12:53:03AM -0500, Tyler Montney wrote:
> Perfect, all of that makes sense. Here's 3 more:
You might try the book by Patrick and Ralf, the basics haven't changed.
> - The way I understand master.cf is that it spins up services.
On demand, unless some idle instances of the service are already up and
running and waiting for requests.
> For instance, the smtpd service to accept incoming connections on
> port 25,
These spin up on demand and exit after a number of requests or when idle
too long. A lightly loaded system might not have any running much of
the time.
> or qmgr that handles the various queues (like active and deferred).
The qmgr(8) daemon runs indefinitely, until a "stop" or "reload".
> For other services that wish to interact with say 'verify', how do
> they do this?
By connecting to the service socket.
> Would it be accurate to compare it to an HTTP routing table?
The inetd(8) service and inetd.conf file is a better analogy.
> They call postfix with the service name, and in turn get the
> executed command?
No. They connect to the relevant public or private socket, and the
service is started if not already running or busy and the process limit
has not been reached.
> - Why are Postfix manual pages for these services identical?
> - smtp/lmtp
Same program implements multiple services.
> - bounce/defer/trace
Same program implements multiple services.
> - Is there any documentation for the service 'relay'?
It is an smtp(8) transport, see smtp(8) and ADDRESS_CLASS_README.
For more basic background questions, let Patrick and Ralf earn some
royalties, and:
http://www.postfix.org/OVERVIEW.html
http://www.postfix.org/BASIC_CONFIGURATION_README.html
http://www.postfix.org/STANDARD_CONFIGURATION_README.html
and other documents at:
http://www.postfix.org/documentation.html
--
Viktor.
