Server Software and Configuration Services
cPanel breaks your MTA with 11.23.0-EDGE_24083 and 11.23.0-CURRENT_24083
If you’re running either of the listed builds above, then you could have a broken MTA.For some bizarre reason, cPanel decided to add a new feature that breaks the standard MTA configuration of sending out all email on a servers main IP address. Their change is to send it out on the IP address of the sending domain. This means that unless all your rDNS PTR records for all of your servers IP addresses are set to your hostname a large number of receiving MTA’s on the internet will either treat incoming email as spam or simply bounce it.In their wisdom, cPanel have made this massive MTA change as the new default in EDGE and CURRENT, changing the status quo without your knowledge or indeed control. You cannot currently disable this change and revert back to the way the MTA should work.In the short term, you can delete /etc/mailips and add a line to /scripts/postupcp to remove that file, however this still leaves a window between upcp running /scripts/updateuserdomains and /scripts/postupcp running when your outgoing email could be broken.Apparently this change was made to benefit the use of SPF records. Since that technology has proven to provide little or no benefit, and there are no requirements whatsoever in the MTA RFC’s to use SPF, it seems bizarre that cPanel has taken this route as their default configuration.Note: MTA ~ SMTP Server