[wp-trac] [WordPress Trac] #49687: wp_mail() - Why is no envelope sender defined?

[WordPress Trac]

#49687: wp_mail() - Why is no envelope sender defined?
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 Reporter:  vbbp                            |       Owner:  SirLouen
     Type:  enhancement                     |      Status:  accepted
 Priority:  normal                          |   Milestone:  6.9
Component:  Mail                            |     Version:  5.4
 Severity:  major                           |  Resolution:
 Keywords:  has-test-info has-patch commit  |     Focuses:
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Comment (by dmsnell):

 After considerable help from @stankea and @websupporter we have confirmed
 a few things, most notably a confirmation that this patch should be
 appropriate.

  - In `trunk` the Sender/Envelope From is being set incorrectly due to the
 `false` flag. It’s likely picking up an unreachable hostname from the mail
 server.
  - With the patch WordPress //by default// is using the domain “where the
 front end is accessible” and `wordpress` as the user.

 This is generally correct. //However// there might be one case where this
 breaks existing sites: //if// the site has a SPF which does not allow
 sending emails on behalf of this site domain, then other mail hosts might
 start rejecting emails from it where they may have let through the
 previously-configured host. Granted, //this is an odd configuration// and
 for sites where //advanced mail setup has already taken place//. It is
 likely that if someone configures SPF they will probably add the
 appropriate domain in the policies. Even then, if the site has a working
 DKIM+DMARC configuration it will likely bypass this SPF failure.

 All in all it seems like this is an appropriate change, and should
 anything drastic come up we can always revert. I will be merging this now.
 Thank you everyone for your help, reporting, testing, explanations, and
 double-checking.

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Ticket URL: <https://core.trac.wordpress.org/ticket/49687#comment:36>
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