<div dir="auto"><div dir="auto">Thank you</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Jul 3, 2023, 3:41 PM Michael Stauber via Blueonyx <<a href="mailto:blueonyx@mail.blueonyx.it">blueonyx@mail.blueonyx.it</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Tim,<br>
<br>
> 5210R<br>
> <br>
> I am pondering switching from sendmail to postfix.<br>
> <br>
> Anything that I should be aware of with regard to what is going to <br>
> change regarding my client's email client setups?<br>
> <br>
> Is there anything that they will have to change in their settings?<br>
> <br>
> Can I switch back if I suddenly run into issues (my clients)<br>
<br>
On 5210R/5211R you can switch between Sendmail and Postfix at any time <br>
and in either direction. Typically the clients won't even notice and no <br>
config changes are required server side or client side.<br>
<br>
The main difference between Sendmail and Postfix (as far as BlueOnyx <br>
goes) is this:<br>
<br>
Postfix supports SNI. So it will make use of *all* SSL certificates. <br>
That includes the GUI's cert and the SSL cert of all Vsites that have <br>
SSL enabled.<br>
<br>
Whereas Sendmail could only use a single SSL certificate and therefore <br>
only used the GUI's SSL cert.<br>
<br>
With Postfix your clients (who have SSL enabled on their Vsite) no <br>
longer get an SSL certificate mismatch if they use SMTPS, POPS or IMAPS <br>
and their configured mail-endpoint on the BlueOnyx is the domain name of <br>
their Vsite.<br>
<br>
Of course: If you ever have clients who use *that* setup and switch back <br>
from Postfix to Sendmail? Yeah, then they get the "certificate mismatch" <br>
again, because Sendmail only uses the GUI cert, which doesn't have <br>
provisions for any Vsite SSL.<br>
<br>
Other than that? Postfix is more robust and takes abuse a lot better <br>
than Sendmail. The way we have Postfix set up on BlueOnyx is that each <br>
time when Postfix is started it parses the Sendmail configuration and <br>
creates a new Postfix configuration on the fly. That way the <br>
configuration of both MTAs remains identical and "doesn't drift apart".<br>
<br>
Should you ever wish to configure Postfix differently than the GUI <br>
allows, or want to set a parameter that the GUI doesn't have for the <br>
Postfix configuration? You can put your changes into this script, which <br>
will never be overwritten by YUM updates:<br>
<br>
/usr/sausalito/bin/custom-postfix-confgen.sh<br>
<br>
There is an example in that file that shows how it's done. This script <br>
runs at the end of the auto-configure of Postfix that happens during <br>
each Postfix restart. So you have full flexibility of how you want to <br>
configure that service if you want to tweak it further than the GUI allows.<br>
<br>
Let me know if you have any further questions and I'd be glad to help.<br>
<br>
-- <br>
With best regards<br>
<br>
Michael Stauber<br>
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</blockquote></div>