Virtualmin 3.88 gpl / Webmin 1.570
Webmin Configuration > Sending Email
The default 'From address for email from Webmin' is still used even if an alternate address is entered. See also artifact ID: 3413156
This will be fixed in Webmin 1.580.
This is NOT fixed in 1.580 either - needs to be re-opened.
If someone needs manual fix, in two files:
find and replace 'webmin_addr' with 'webmin_from'
Or, you may just manually edit /etc/webmin/mailboxes/config - webmin uses webmin_from config setting in mailboxes-lib.pl as from address.
Also, there is another related issue - the default from domain for users cannot be set from UI (at least I couldn't find how to do so). This is useful setting to allow manually sending emails with correct from addresses.
Correct domain can be specified in /etc/webmin/mailboxes/config file as from_dom parameter.
I hope, this can be fixed in the next release - those are small fixes, which should be easy to correct and will save lots of time for people trying to make email working correctly.
You are correct - it isn't setting the correct option. I will fix this in the next Webmin release (1.590).