Maybe this is the issue?  I am seeing TLSv1?  I think Microsoft deprecated that.  I have tried to update the config file but cannot get it to show anything but v1.

 

Global options:

debug                  = daemon.notice

pid                    = /var/run/stunnel.pid

RNDbytes               = 64

RNDfile                = /dev/urandom

RNDoverwrite           = yes

 

Service-level options:

ciphers                = FIPS (with "fips = yes")

ciphers                = ALL:!SSLv2:!aNULL:!EXP:!LOW:-MEDIUM:RC4:+HIGH (with "fips = no")

curve                  = prime256v1

sessionCacheSize       = 1000

sessionCacheTimeout    = 300 seconds

sslVersion             = TLSv1 (with "fips = yes")

sslVersion             = TLSv1 for client, all for server (with "fips = no")

stack                  = 65536 bytes

TIMEOUTbusy            = 300 seconds

TIMEOUTclose           = 60 seconds

TIMEOUTconnect         = 10 seconds

TIMEOUTidle            = 43200 seconds

verify                 = none

 

From: Ben Bazian via stunnel-users <[email protected]>
Sent: Tuesday, October 26, 2021 10:55 AM
To: jose isaias cabrera <[email protected]>; [email protected]
Subject: [stunnel-users] Office 365 connections stopped working

 

[E X T E R N A L]

This has been working for years and recently stopped.  I am a novice here.  Can someone look at this and please tell me what is happening?  It is an old server that does not support TLS so we put Stunnel in front of it.  I am sure the version of stunnel is pretty old.  Maybe a TLS level issue?

 

2021.10.26 14:47:30 LOG7[21968:139797665822784]: SSL options set: 0x01000004

2021.10.26 14:47:30 LOG6[21968:139797665822784]: Initializing service [SMTP Outgoing]

2021.10.26 14:47:30 LOG7[21968:139797665822784]: SSL options set: 0x01000004

2021.10.26 14:47:30 LOG6[21968:139797665822784]: Initializing service [IMAP]

2021.10.26 14:47:30 LOG7[21968:139797665822784]: SSL options set: 0x01000004

2021.10.26 14:47:30 LOG5[21968:139797665822784]: Configuration successful

2021.10.26 14:47:30 LOG7[21968:139797665822784]: Service [POP3 Incoming] (FD=12) bound to 0.0.0.0:110

2021.10.26 14:47:30 LOG7[21968:139797665822784]: Service [SMTP Outgoing] (FD=13) bound to 0.0.0.0:25

2021.10.26 14:47:30 LOG7[21968:139797665822784]: Service [IMAP] (FD=14) bound to 0.0.0.0:143

2021.10.26 14:47:30 LOG7[21974:139797665822784]: Created pid file /var/run/stunnel.pid

2021.10.26 14:48:30 LOG7[21974:139797665822784]: Service [IMAP] accepted (FD=3) from 10.55.3.159:1852

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Service [IMAP] started

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Waiting for a libwrap process

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Acquired libwrap process #0

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Releasing libwrap process #0

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Released libwrap process #0

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Service [IMAP] permitted by libwrap from 10.55.3.159:1852

2021.10.26 14:48:30 LOG5[21974:139797665818368]: Service [IMAP] accepted connection from 10.55.3.159:1852

2021.10.26 14:48:30 LOG6[21974:139797665818368]: connect_blocking: connecting 52.96.87.226:993

2021.10.26 14:48:30 LOG7[21974:139797665818368]: connect_blocking: s_poll_wait 52.96.87.226:993: waiting 10 seconds

2021.10.26 14:48:30 LOG5[21974:139797665818368]: connect_blocking: connected 52.96.87.226:993

2021.10.26 14:48:30 LOG5[21974:139797665818368]: Service [IMAP] connected remote server from 10.55.3.200:51358

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Remote socket (FD=16) initialized

2021.10.26 14:48:30 LOG7[21974:139797665818368]: SNI: sending servername: outlook.office365.com

2021.10.26 14:48:30 LOG7[21974:139797665818368]: SSL state (connect): before/connect initialization

2021.10.26 14:48:30 LOG7[21974:139797665818368]: SSL state (connect): SSLv3 write client hello A

2021.10.26 14:48:30 LOG3[21974:139797665818368]: SSL_connect: Peer suddenly disconnected

2021.10.26 14:48:30 LOG5[21974:139797665818368]: Connection reset: 0 byte(s) sent to SSL, 0 byte(s) sent to socket

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Remote socket (FD=16) closed

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Local socket (FD=3) closed

2021.10.26 14:48:30 LOG7[21974:139797665818368]: Service [IMAP] finished (0 left)