BACKGROUND
I recently setup an email server (using postfix) for a 160 email users.
I created an alias all_user@mycompany.com to all users.


PROBLEM
Unfortunately, external email users from yahoo, hotmail, etc can send email to that alias all_user.

I want to restrict only local users can send email to the alias all_user@mycompany.com



can anyone help me out in solving this problem? thanks and god bless! im currently looking at smtpd_recipient_restrictions .

Thanks in advanced and god bless!

- dm0nkz

Sorry if this workaround doesn't suit your needs, but if this machine is only to serve local mail (this is the assumption I'm not sure is applicable), why not just block traffic from external sources?

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edit: I've never used postfix, so cheating was the only idea I had. But if you want a SOLID answer, refer to the post by r0b0 below.

PS: dm0nkz, I want to point out that your question is VERY well set up and formatted. Maybe that's why I felt the need to reply in the first place, because your question is phrased so well I almost felt like I knew what I was doing.
;)

Check out the excelent tips from Ralf Hildebrandt especially Postfix smtpd_restriction_classes for Dummies and Part 2 and Part 3.
R.