SNI Dovecot

Aki Tuomi aki.tuomi at
Fri Aug 31 14:16:34 EEST 2018

2.2.10 is quite old. try reproducing this with .36 or

---Aki TuomiDovecot oy
-------- Original message --------From: Martin Johannes Dauser <mdauser at> Date: 31/08/2018  13:10  (GMT+02:00) To: dovecot at Subject: Re: SNI Dovecot 
dovecot 2.2.10 from RedHat 7 has an issue with clients, which won't send SNI. As you are using version 2.2.27 you might encounter the same behaviour.
If the client won't send SNI, my server randomly answers with any cert instead of the default cert,  --Perhaps dovecot just utilises the last used cert? One speciality of my certs is, that both share the same Common Name (CN) but differ in Subject Alternative Names (SAN).
Once your config works, you can check by initialising several connections (I tried 30 times) without SNI using openssl. First command is without SNI, second is with SNI.
$ openssl s_client -showcerts -connect IP-address:993
$ openssl s_client -showcerts -connect IP-address:993 -servername server.domain 
This is my bugreport on this list.

Best regardsMartin Johannes Dauser

On Wed, 2018-08-29 at 14:41 +0000, Nicolas wrote:
 Hi all,

I'm testing the SNI configuration from dovecot's wiki page, to have multiple domains.

I'm using letsencrypt certificates.
  On the 10-ssl.conf, when I only use one domain, like this, it works :

ssl_ca = </etc/letsencrypt/live/
ssl_cert = </etc/letsencrypt/live/
ssl_key = </etc/letsencrypt/live/

I got a warning of course when using my second domain,

If I do the config :

local_name {
ssl_ca = </etc/letsencrypt/live/
ssl_cert = </etc/letsencrypt/live/
ssl_key = </etc/letsencrypt/live/

local_name {
ssl_ca = </etc/letsencrypt/live/
ssl_cert = </etc/letsencrypt/live/
ssl_key = </etc/letsencrypt/live/

I got this on dovecot's start :

dovecot[930]: master: Error: service(imap-login): command startup failed, throttling for 8 secs
dovecot[932]: imap-login: Fatal: Couldn't parse private ssl_key: error:0906D06C:PEM routines:PEM_read_bio:no start line: Expecting: ANY PRIVATE KEY

It's working without local_name, so why it can be a certificate issue?

Any idea?

I'm using dovecot 2.2.27-3+deb9u2 from debian.

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