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@lists.domain.tld> ORCPT=rfc822;list-bounces@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@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