On Tue, Aug 15, 2017 at 08:20:51PM +0400, Mohammed Khalid Ansari wrote:
> Can I use multiple instances of postfix on the same host with different
> ports like 25 and 587?
Each instance has its own master.cf file. The "inet" entries in
that file, toghether with the inet_interfaces setting determine
which TCP listener endpoints are handled by that instance.
By default, newly created instances have all "inet" services disabled
via "master_service_disable". After your master.cf file matches
your requirements, you can re-enable them and reload the instance.
> I understand I can start one instance with port 25 and then change the port
> in master.cf and start another one. Will that be OK??? Has anyone tried
> that??
Running multiple instances each with an appropriate master.cf is
the purpose of multi-instance support in Postfix. All that you
need to do is to ensure that no instances attempt to bind the same
service IP:port combination (the wildcard IP address generally
conflicts with any explicit address on various operating systems).
> I don't want to try on my host right now as it would be difficult for me to
> fix if something goes wrong.
Just stop any unwanted instances, and revert any (usually minor)
changes to the configuration of the default instance.
Multiple instances are *easier* to work with than a single monolithic
system once your requirements get sufficiently complicated.
--
Viktor.
