Bounce from "destination server" as SPAM - header/received too short!
glenn.steen at gmail.com
Mon Nov 10 17:16:30 GMT 2014
Actually... All you need do is configure recipient verification in postfix
(this is in-built and documented well several places, like the postfix doc
site or the MailScanner wiki). Alternatively maintain a relay recipient map
or an access map (both are fairly trivial to set up).
Doing any of these will reject instead of bounce, for unknown recipients.
Flip side of the coin is that you may expose your recipient "universe", for
easy mapping (regardless if you have disabled vrfy), but... That's just how
Den 10 nov 2014 14:03 skrev "Joolee" <mailscanner at joolee.nl>:
> Quite an easy solution is to simply don't bounce. E-mail to non-existing
> users is probably (uncought) spam and they rarely come from legit e-mail
> addresses. You are spamming the actual owners of the e-mail addresses being
> abused by sending backscatter to them. It might even get you listed on a
> backscatter dnsbl.
> If you want to provide legit mail senders with a "this user doesn't exist"
> message, configure all legit users on your edge server so mail to
> non-existing users is being blocked on smtp level. (This will also reject
> ~90% of spam) The sending party can than implement any backscatter/messages
> they want with this information, it's not your problem.
> On 10 November 2014 12:44, Sim <simvirus at gmail.com> wrote:
>> Hello to all!
>> I've a little issue...
>> SENDER (from test at extenal.com to nomail at mydomain) ------> *MailScanner
>> *-----> Mailbox Server (@mydomain)
>> At this time my internal "Mailbox Server" generate a bounce for not
>> exiting "nomail" account.
>> This bounce is detected as SPAM from MailScanner.
>> - The IP of Mailbox Server is in "Whitelist"
>> - The LAN (/24) of Mailbox Server is in "Trusted Network"
>> - The LAN (/24) of Mailbox Server is in "Outbound mail relay"
>> - All other email sent from "Mailbox Server" are detected as "white list"
>> Checking the log of postfix i've found this:
>> postfix/cleanup: C1C2960069: hold: header Received: from
>> srv.mydomain.local (unknown [192.168.0.10])??(using TLSv1 with cipher
>> AES128-SHA (128/128 bits))??(No client certificate requested)??by
>> mail.mydomain.com (Postfix) w from unknown[192.168.0.10]; from=<> to=<
>> test at external.com> proto=ESMTP helo=<srv.mydomain.local>
>> MailScanner: Spam Checks: Starting
>> MailScanner: Message C1C2960069.AEB15 from 192.168.0.10 has no (or
>> invalid) watermark or sender address, marked as high-scoring spam
>> MailScanner: Spam Checks: Found 1 spam messages
>> The header of postifx/cleanup is incomplete!!!!
>> Looking for full header i've seen: "(Postfix) with ESMTPS id
>> C1C2960069?" and not only "(Postfix) w"
>> How to increase this "check of the header limit" in postfix, cleanup or
>> MailScanner ?
>> MailScanner mailing list
>> mailscanner at lists.mailscanner.info
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