From: Michael Katz (mknewsmessagepartners.com)
Date: Thu Feb 07 2008 - 10:43:03 CST

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Alejandro Facultad wrote:
> Noel Jones wrote:
>> Alejandro Facultad wrote:
>>> Dear all, I have Postfix 2.3.8 as my mail server and I want this: if
>>> someone write a message to a non existant mail account from my domain,
>>> he/she must get a response code = 250 and not 550. I want the same
>>> response code that he/she will obtain in case of writting to an
>>> existing mail account.
>>>
>>> I edit the main.cf adding "reject_unverified_recipient" and
>>> "unverified_recipient_reject_code = 250" in this way but people
>>> writting to a non valid mail account still get the 550 error code:
>>>
>>> smtpd_recipient_restrictions =
>>> check_recipient_access hash:/etc/postfix/access
>>> permit_mynetworks
>>> reject_unknown_sender_domain
>>> reject_unauth_destination
>>> check_policy_service unix:private/policy
>>> reject_unverified_recipient
>>>
>>>
>>> unverified_recipient_reject_code = 250
>>>
>>> Thanks in advance
>>>
>>> Alejandro
>> What exactly is the point of this? This sounds like a really bad idea.
>>
>> Don't use reject_unverified_recipient if you don't want to reject unverified recipients.
>>
>
> Noel, I want people from Internet that send messages to non existant
> users from my domain they don't get an error code (550) but they must
> get an 250 success code. They don't have to know which mail accounts
> are valid or invalid, they must see ALL accounts as valid, because
> nowadays there are a lot of intruders getting our mail accounts,
> probing time after time via telnet port 25 and if they get code 250
> they get a valid account. We want the intruders always get code 250 so
> they can't discriminate between valid and invalid mail accounts.
>
> I work for a company with strong security policies for mail accounts.

I work with many customers that have this request for all types of
non-technical reasons. Just turn off recipient verification as everyone
else says, its functionality is contrary to your requirement.
>
> Thanks a lot.
>
>
>
>
>

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