Hi Victor, thank you for your kind reply. That explains a lot, i did not know. Also i now realize looking at the timestamps that it is indeed one and the same message. I feel stupid now. But i will remember that inbound smtp is anonymous.
Thanks. > On 16 Aug 2017, at 13:40, Viktor Dukhovni <[email protected]> wrote: > > >> On Aug 16, 2017, at 8:11 AM, Alef Veld <[email protected]> wrote: >> >> 2. Why do i sometimes get a anonymous TLS connection. > > Inbound SMTP email is "always" anonymous, as servers generally > don't and should not request client certificates, and even if > they did, clients wouldn't generally be configured to present > such certificates. See: > > http://www.postfix.org/FORWARD_SECRECY_README.html#status > >> Aug 16 09:01:47 www postfix/smtpd[12706]: SSL_accept:SSLv3 flush data > > Your log level is too high, set it to 1, and you'll get better > performance, and fewer debugging messages that you find confusing. > It may even be that with all debugging logging flooding the log > server, some messages are getting lost. Though in this case both > the first connection: > >> Aug 16 09:01:47 www postfix/smtpd[12706]: Anonymous TLS connection >> established from >> mail-oln040092068076.outbound.protection.outlook.com[40.92.68.76]: TLSv1.2 >> with cipher AES256-SHA256 (256/256 bits) >> >> And sometimes a regular TLS connection ? Same ip and same cipher as well. > > (actually also anonymous, just a few extra lines you happened to cut/paste) > >> Aug 16 09:01:47 www postfix/smtpd[12706]: initializing the server-side TLS >> engine >> Aug 16 09:01:47 www postfix/smtpd[12706]: connect from >> mail-oln040092068076.outbound.protection.outlook.com[40.92.68.76] >> Aug 16 09:01:47 www postfix/smtpd[12706]: setting up TLS connection from >> mail-oln040092068076.outbound.protection.outlook.com[40.92.68.76] >> Aug 16 09:01:47 www postfix/smtpd[12706]: >> mail-oln040092068076.outbound.protection.outlook.com[40.92.68.76]: TLS >> cipher list "ALL:+RC4:@STRENGTH" > > and the second connection: > >> >> Aug 16 09:01:47 www postfix/smtpd[12706]: Anonymous TLS connection >> established from >> mail-oln040092068076.outbound.protection.outlook.com[40.92.68.76]: TLSv1.2 >> with cipher AES256-SHA256 (256/256 bits) > > are anonymous. The above log entries are all for the same inbound > TLS session. > > -- > Viktor. >
