Bouncing messages with missing From: info

[Steve Freegard]

The Exchange default (really stupid) is not to reject non-existent 
users, so even if you are doing an SMTP call-ahead to verify recipients 
it won't do any good unless Exchange is configured to reject invalid users.

See http://technet.microsoft.com/en-us/library/bb125187.aspx

Also note that a From header is mandatory for all messages see RFC5322 
section 3.6.  For bounce messages the envelope sender is null to prevent 
mail loops, the from header is usually MAILER DAEMON or 
postmaster at generating.host.name.

Regards,
Steve.

On 15/04/13 16:56, Raymond Norton wrote:
> I have the following in main.cf:
>
> smtpd_restriction_classes = spf_policy, grey_policy, whitelist_policy
> verify_recipient, look_ahead
>
> Yet, the relay domain on my end is getting hammered with undeliverables
> to non-existant users. They are using Exchange 2010 and I have verified
> their server sends out a 550 message, but would like them not to have to
> deal with the messages in the first place.
>
>
>
> On 04/15/2013 10:17 AM, Jerry Benton wrote:
>> NDRs are not supposed to have info in the From field according to RFC.
>> That prevents emails bouncing around until the end of time.
>>
>> So, are these NDRs to real users? If not, you can use recipient
>> verification.
>>
>> References:
>>
>> tools.ietf.org/html/rfc3834 <http://tools.ietf.org/html/rfc3834>
>>
>> tools.ietf.org/html/rfc2822 <http://tools.ietf.org/html/rfc2822>
>>
>> tools.ietf.org/html/rfc5321 <http://tools.ietf.org/html/rfc5321>
>>
>> tools.ietf.org/html/rfc6522 <http://tools.ietf.org/html/rfc6522>
>>
>>
>> On Mon, Apr 15, 2013 at 3:43 PM, Raymond Norton <admin at lctn.org
>> <mailto:admin at lctn.org>> wrote:
>>
>>     I am using MailScanner 4.84.5 with postfix. I have one relay domain
>>     getting hit hard by  non delivery notices which are missing any
>>     info in
>>     the "From" field.
>>
>>     Is there a rule I can add to postfix that will bounce messages
>>     like this?
>>
>>
>>     Raymond
>>     --
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>>
>>
>>
>> --
>>
>> --
>> Jerry Benton
>> Mailborder Systems
>> www.mailborder.com <http://www.mailborder.com>
>>
>> --
>> This message has been scanned for viruses and
>> dangerous content by *MailScanner* <http://www.mailscanner.info/>, and is
>> believed to be clean.
>>
>>
>
>
>