Hi,
We cannot get stunnel SMTP to work with Office 365 mail server. We are using Stunnel 5.13 and below are the config file content and the the client PC logs. The mail server logs do not reveal anything more.
Two observations of the test setup:
1) Using e.g. Mozilla Firebird mail client directly SLL/SMTP on the same PC connection to same Office 365 mail server works ok, but via Stunnel it outputs the error log below.
2) Also, on the same PC, SSL/SMTP connection via stunnel to Gmail server works ok.
Stunnel conf-file: ==============
output = stunnel_log.txt debug = debug cert = tstunnel.pem client = yes
[SSMTP] accept = 127.0.0.1:54500 connect = xxx.xxx.xxx.xxx:587 (Hannu V: removed IP address from this mail) protocol = smtp
Client PC logs: ===========
2015.04.28 09:17:36 LOG7[ui]: No limit detected for the number of clients 2015.04.28 09:17:36 LOG5[ui]: stunnel 5.13 on x86-pc-msvc-1500 platform 2015.04.28 09:17:36 LOG5[ui]: Compiled/running with OpenSSL 1.0.2a 19 Mar 2015 2015.04.28 09:17:36 LOG5[ui]: Threading:WIN32 Sockets:SELECT,IPv6 TLS:ENGINE,FIPS,OCSP,PSK,SNI 2015.04.28 09:17:36 LOG7[ui]: errno: (*_errno()) 2015.04.28 09:17:36 LOG5[ui]: Reading configuration from file tstunnelSmtp_SAUX1_0.conf 2015.04.28 09:17:36 LOG5[ui]: UTF-8 byte order mark not detected 2015.04.28 09:17:36 LOG5[ui]: FIPS mode disabled 2015.04.28 09:17:36 LOG7[ui]: Compression disabled 2015.04.28 09:17:36 LOG7[ui]: PRNG seeded successfully 2015.04.28 09:17:36 LOG6[ui]: Initializing service [SSmtp] 2015.04.28 09:17:36 LOG6[ui]: Loading certificate from file: tstunnel.pem 2015.04.28 09:17:36 LOG6[ui]: Loading key from file: tstunnel.pem 2015.04.28 09:17:36 LOG7[ui]: Private key check succeeded 2015.04.28 09:17:36 LOG7[ui]: SSL options: 0x03000004 (+0x03000000, -0x00000000) 2015.04.28 09:17:36 LOG5[ui]: Configuration successful 2015.04.28 09:17:36 LOG7[ui]: Listening file descriptor created (FD=448) 2015.04.28 09:17:36 LOG7[ui]: Service [SSmtp] (FD=448) bound to 127.0.0.1:8030 2015.04.28 09:17:36 LOG7[ui]: Service [SSmtp] accepted (FD=456) from 127.0.0.1:54500 2015.04.28 09:17:36 LOG7[ui]: Creating a new thread 2015.04.28 09:17:36 LOG7[ui]: New thread created 2015.04.28 09:17:36 LOG7[0]: Service [SSmtp] started 2015.04.28 09:17:36 LOG5[0]: Service [SSmtp] accepted connection from 127.0.0.1:54500 2015.04.28 09:17:36 LOG6[0]: s_connect: connecting xxx.xxx.xxx.xxx:587 (Hannu V: removed IP address from this mail) 2015.04.28 09:17:36 LOG7[0]: s_connect: s_poll_wait connecting xxx.xxx.xxx.xxx:587 : waiting 10 seconds (Hannu V: removed IP address from this mail) 2015.04.28 09:17:37 LOG5[0]: s_connect: connected connecting xxx.xxx.xxx.xxx:587 (Hannu V: removed IP address from this mail) 2015.04.28 09:17:37 LOG5[0]: Service [SSmtp] connected remote server from yyy.yyy.yyy.yyy:54503 (Hannu V: removed IP address from this mail) 2015.04.28 09:17:37 LOG7[0]: Remote socket (FD=472) initialized 2015.04.28 09:17:37 LOG7[0]: <- 220 NNN.outlook.office365.com Microsoft ESMTP MAIL Service ready at Tue, 28 Apr 2015 14:17:38 +0000 2015.04.28 09:17:37 LOG7[0]: -> 220 NNN.outlook.office365.com Microsoft ESMTP MAIL Service ready at Tue, 28 Apr 2015 14:17:38 +0000 2015.04.28 09:17:37 LOG7[0]: -> EHLO localhost 2015.04.28 09:17:37 LOG7[0]: <- 250-NNN.outlook.office365.com Hello [xxx.xxx.xxx.161] (Hannu V: removed IP address from this mail) 2015.04.28 09:17:37 LOG7[0]: <- 250-SIZE 157286400 2015.04.28 09:17:37 LOG7[0]: <- 250-PIPELINING 2015.04.28 09:17:37 LOG7[0]: <- 250-DSN 2015.04.28 09:17:37 LOG7[0]: <- 250-ENHANCEDSTATUSCODES 2015.04.28 09:17:37 LOG7[0]: <- 250-STARTTLS 2015.04.28 09:17:37 LOG7[0]: <- 250-8BITMIME 2015.04.28 09:17:37 LOG7[0]: <- 250-BINARYMIME 2015.04.28 09:17:37 LOG7[0]: <- 250 CHUNKING 2015.04.28 09:17:37 LOG7[0]: -> STARTTLS 2015.04.28 09:17:37 LOG7[0]: <- 220 2.0.0 SMTP server ready 2015.04.28 09:17:37 LOG6[0]: SNI: sending servername: NNN.office365.com 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): before/connect initialization 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv2/v3 write client hello A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 read server hello A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 read server certificate A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 read server key exchange A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 read server certificate request A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 read server done A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 write client certificate A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 write client key exchange A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 write certificate verify A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 write change cipher spec A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 write finished A 2015.04.28 09:17:37 LOG7[0]: SSL state (connect): SSLv3 flush data 2015.04.28 09:17:37 LOG3[0]: SSL_connect: Peer suddenly disconnected 2015.04.28 09:17:37 LOG5[0]: Connection reset: 0 byte(s) sent to SSL, 0 byte(s) sent to socket 2015.04.28 09:17:37 LOG7[0]: Remote socket (FD=472) closed 2015.04.28 09:17:37 LOG7[0]: Local socket (FD=456) closed 2015.04.28 09:17:37 LOG7[0]: Service [SSmtp] finished (0 left)
--- Hannu