[BlueOnyx:24028] Re: TLS handshake failing in Sendmail

[Michael Stauber]

Hi Ernie,

> I tried that, now I get the following errors with outlook.com
> 
> Jun 19 16:36:49 bx3 sendmail[25225]: STARTTLS=server, relay=mail-eopbgr1310103.outbound.protection.outlook.com [40.107.131.103], version=TLSv1.2, verify=OK, cipher=ECDHE-RSA-AES256-GCM-SHA384, bits=256/256
> Jun 19 16:36:51 bx3 sendmail[25225]: STARTTLS: write error=syscall error (-1), errno=104, get_error=error:00000000:lib(0):func(0):reason(0), retry=99, ssl_err=5


That "errno=104" means they unexpectedly closed the connection. And
"ssl_err=5" means "SSL_ERROR_SYSCALL".

    SSL_ERROR_SYSCALL:

    Some I/O error occurred.  The OpenSSL error queue may contain more
    information on the error.  If the error queue is empty (i.e.
    ERR_get_error() returns 0), ret can be used to find out more about
    the error: If ret == 0, an EOF was observed that violates the pro-
    tocol.  If ret == -1, the underlying BIO reported an I/O error (for
    socket I/O on Unix systems, consult errno for details).

The client or MTA at the outlook end of things probably closed the
connection abruptly, and a likely reason for this is that it simply
crashed when trying to do the TLS handshake. Sounds like a Windows thing
to me.

-- 
With best regards

Michael Stauber