On Wed, Apr 27, 2022 at 10:43:33PM +0200, Vincent Lefevre wrote: > On 2022-04-27 11:29:17 -0400, Greg Wooledge wrote: > > So if your /etc/mailname contains lenin.histomat.net then mail sent by > > john on your system may(!) have a default(!) from/sender address of > > john@lenin.histomat.net. Unless it's overridden. > > > > If what you WANT is for your outgoing mail to appear to come from > > john@histomat.net then you should have histomat.net in that file instead. > > > > The fact that lenin.histomat.net has no MX or A records in global DNS > > means it's completely unsuitable for being the right-hand side of an > > email address. So, what you have now is clearly not correct. > > No, this is not necessarily incorrect. If mail is sent locally, > this is fine. For mail sent to other machines, 2 things can be > done in such a case: Agreed. The receiving MTA has to be convinced that the one sending the stuff is supposed to. What that takes is up to that MTA's admin. For example, the sender could provide a cerrtificate for the SMTPS session (I've set up systems like that). Of course, a random MTA contacting "me" with no MX record is either misconfigured or (more probably) a low-cost spammer, so I'll tend to reject that. Cheers -- t
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