[Mailman-Users] Meaning of "Postfix SMTP server: errors from dd11328.otherdomain.tld[ip.ip.ip.ip]"

[Kala Balik]

Dear Mark,

thank you for your helpful reply although your answer shows that my
question was off the list topic.

Am 10.05.2016 um 17:24 schrieb Mark Sapiro:
> On 5/9/16 2:04 PM, Kala Balik wrote:
>>
>> today we ran our first mailing over our new Mailman instance. We
>> received a few bounces and the following email which left me clueless.
>>
>> Please, what is this message trying to tell me? Is this us sending out,
>> or is this someone trying to answer to our mailing (and failing to log
>> in via TLS)? I checked my /var/log/mail logs - to no avail.
> 
> 
> This apparently has nothing directly to do with Mailman on your server.
> 
> 
>> Transcript of session follows.
>>
>>  Out: 220 lists.domain.tld ESMTP Postfix (Ubuntu)
>>  In:  EHLO dd11328.otherdomain.tld
>>  Out: 250-lists.domain.tld
>>  Out: 250-PIPELINING
>>  Out: 250-SIZE 10240000
>>  Out: 250-VRFY
>>  Out: 250-ETRN
>>  Out: 250-STARTTLS
>>  Out: 250-ENHANCEDSTATUSCODES
>>  Out: 250-8BITMIME
>>  Out: 250 DSN
>>  In:  STARTTLS
>>  Out: 454 4.7.0 TLS not available due to local problem
>>  In:  MAIL FROM:<> SIZE=236
>>  Out: 250 2.1.0 Ok
>>  In:  RCPT TO:<list-bounces at lists.domain.tld>
>>      ORCPT=rfc822;list-bounces at lists.domain.tld
>>  Out: 250 2.1.5 Ok
>>  In:  RSET
>>  Out: 250 2.0.0 Ok
>>  In:  QUIT
>>  Out: 221 2.0.0 Bye
> 
> 
> It looks to me like the server that identifies itself as
> dd11328.otherdomain.tld started to send a message (probably a legitimate
> bounce of a list message) to <list-bounces at lists.domain.tld>. It send
> the RCPT TO:, was sent an OK in reply and then instead of sending the
> DATA, reset the connection and quit. Possibly this is because the
> sending server requires TLS which your Postfix says is not available.
> 
> Why your Postfix decided to notify you of this is a Postfix question.
> 
> I suggest you set both
> 
> smtp_tls_security_level = may
> 
> and
> 
> smtpd_tls_security_level = may
> 
> in your Postfix main.cf so that you accept incoming TLS if offered and
> offer outgoing TLS. You will also need to set smtpd_tls_cert_file and
> smtpd_tls_key_file and maybe others. See
> <http://www.postfix.org/TLS_README.html>.
> 
Will implement these postfix changes as soon as possible.
Cordially, KB