On 11.08.2023 19:09, Roberto C. Sánchez wrote:
I am running a Courier IMAP server on Bookworm.
When accessing from mutt, Thunderbird, and Android (GMail app),
everything works fine. This is over SSL, with a server certificate I
have issued from my own CA and with the CA root cert distributed to all
client devices which access the IMAP server.
However, on one particular Android device, I have started to observe
that my account no longer refreshes and when I look in the server logs,
I see a LOGIN, followed by "Unexpected SSL connection shutdown" followed
immediately by a DISCONNECT.
I have seen various postings online about this, but they are mostly from
10+ years ago and have to do with things like people forgetting to trust
the certificate and things of that nature.
I'm wondering if anyone has any sort of thought on what might result in
a single device experiencing this problem when other devices are able to
access the server and the account without issue.
Regards,
-Roberto
It could go wrong for many reasons. Could be a broken SSL\TLS
implementation on that Android device, which usually fixed by firmware
updates.
There also support for different ciphers and SSL\TLS versions. Many of
them are outdated by today's standards and your Android device is
essentially frozen in time.
I have functional Android device which is no longer supported by Google
services and refuses to connect to any websites via HTTPS, mostly
because of outdated Root CA certificates, but it also refuses to connect
to my Samba server for some reason.
I suggest to look for a way to enable debug mode for Courier server and
look for clues in logs.
--
With kindest regards, Alexander.
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