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I did a mailing and the program did not set the envelope adress correctly. So a lot of mails didng go through.

Now I am looking at the mail log and try to find out which mails I need to re-send.

The error codes seem to be somewhat ambigous so I looked at the stat= field.

I found out that the following different values occour:

Sent (-some-message-id Message accepted for delivery)



Deferred: 451 MAIL FROM: <> Unable to verify MX-Record for domain

Deferred: 450 4.1.8 <>: Sender address rejected: Domain not found

Deferred: 421 invalid sender domain '' (misconfigured dns?)

Service unavailable

User Unkown

Data Format Error

Host unknown (Name server: host not found) 

Which do i need to parse out to know which emails didnt go through and need to be re sent?

Invalid sender domain sounds to me like a permanent error. But why is it "Deferred" then?

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up vote 0 down vote accepted

"Deferred" is a non-permanent error. Meaning the mail is not send yet. It will be retried later.

But as you can see in the detailed error message you have a very crippled DNS setup.

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