Postfix VRFY

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Postfix VRFY

Philipp Ewald
Hi folks,

i have just installed postfix on Debian 10 and want to test "SMTP VRFY
Command"

i have noticed that postfix only probing a mail to vrfy the recipient.

Is there any another way as probing mail delivery?
at this point we use a custom script ( we want only "default-tools")

BTW:
by reject_unverified_sender:
would it not be better to check sending server? like accept connection
on port 25 not whole sender? this way dont work with mailing list ( it
would but its produce many mail probing)

Kind regards
Philipp Ewald
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Re: Postfix VRFY

Wietse Venema
Philipp Ewald:
> BTW:
> by reject_unverified_sender:
> would it not be better to check sending server? like accept connection
> on port 25 not whole sender? this way dont work with mailing list ( it
> would but its produce many mail probing)

That would be immensely stupid idea. First, there is no requirement
that a sending MTA can receive email. Second, the sending MTA may
be an email forwarder. The only hosts that can know if the sender
address is valid are the hosts that receive email for that address.

        wietse
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Re: Postfix VRFY

Philipp Ewald
oh damn it...
i don't mean the MTA i think i mean MDA?

i would suggest to check MX-record or/and reply-to or/and SMTP mail from

so postfix can (maybe)probe only [hidden email] and cache the result

Am 20.11.19 um 15:01 schrieb Wietse Venema:

> Philipp Ewald:
>> BTW:
>> by reject_unverified_sender:
>> would it not be better to check sending server? like accept connection
>> on port 25 not whole sender? this way dont work with mailing list ( it
>> would but its produce many mail probing)
>
> That would be immensely stupid idea. First, there is no requirement
> that a sending MTA can receive email. Second, the sending MTA may
> be an email forwarder. The only hosts that can know if the sender
> address is valid are the hosts that receive email for that address.
>
> wietse
>
--
Philipp Ewald
Administrator

DigiOnline GmbH, Probsteigasse 15 - 19, 50670 Köln
Telefon: +49 221 6500-532, Fax: +49 221 6500-690, E-Mail:
[hidden email]

AG Köln HRB 27711, St.-Nr. 5215 5811 0640
Geschäftsführer: Werner Grafenhain

Informationen zum Datenschutz: www.digionline.de/ds