NGINX IMAP proxy and outlook ios/android app

[Anton Yuzhaninov]

On 10/09/17 09:45, bobykus wrote:
> Looks like since mid of Sept  we can not use nginx as an imap(s) proxy for
> mobile outlook apps (both IOS and Android ).
> SSL handshake is just dropping  like

Try to setup a test https site on the same nginx with the same ssl
setting and access this site using default phone browser. May be a
problem is not specific to imap (and mobile outlook).

> 2017/10/09 15:32:01 [debug] 30391#0: *184 accept: 52.166.246.73 fd:44
> 2017/10/09 15:32:01 [info] 30391#0: *184 client 52.166.246.73 connected to
> 0.0.0.0:993
> 2017/10/09 15:32:01 [debug] 30391#0: *184 SSL_do_handshake: -1
> 2017/10/09 15:32:01 [debug] 30391#0: *184 SSL_get_error: 2
> 2017/10/09 15:32:01 [debug] 30391#0: *184 epoll add event: fd:44 op:1
> ev:80000001
> 2017/10/09 15:32:01 [debug] 30391#0: *184 event timer add: 44:
> 60000:1507555981777
> 2017/10/09 15:32:31 [debug] 30391#0: *184 SSL handshake handler: 0
> 2017/10/09 15:32:31 [debug] 30391#0: *184 SSL_do_handshake: 0
> 2017/10/09 15:32:31 [debug] 30391#0: *184 SSL_get_error: 5
> 2017/10/09 15:32:31 [info] 30391#0: *184 peer closed connection in SSL
> handshake while SSL handshaking, client: 52.166.246.73, server:
0.0.0.0:993
...
>
> Wonder how  can I figure out what happened, MS support is not any
helpful in
> this case.
> tcpdump does not show much also...

Do you tried to save traffic dump to a file and study it in Wireshark?
Wireshark can decode Client/Server Hello messages and it can give a
useful hint.