[stunnel-users] Stunnel Crash: Gmail SMTP over TLS

[Shatadal Ghosh]

Hi,

I am using stunnel 4.15 on Windows XP SP1 with Mozilla Thunderbird as
the e-mail client. I do not have openSSL installed locally. I do have
the libssl32.dll and libeay32.dll in the same directory as stunnel.exe
(C:\Program Files\stunnel). I am running stunnel as a service.

Stunnel crashes when I use it to send e-mail (SMTP via TLS) via gmail.

According to the e-mail client configuration page on the gmail website
http://mail.google.com/support/bin/answer.py?answer=13287&topic=1555

I tried to use SMTP over TLS to connect to smtp.gmail.com:587

My gmail-smtps block in stunnel.conf was

; SMTP service, listens on localhost:250
[gmail-smtps]
protocol=smtp
accept=localhost:250
connect=smtp.gmail.com:587

On trying to send an e-mail message via the above configuration stunnel
crashed. The log file is as follows

2006.06.14 03:17:15 LOG5[3956:3512]: stunnel 4.15 on x86-pc-mingw32-gnu
with OpenSSL 0.9.7i 14 Oct 2005
2006.06.14 03:17:15 LOG5[3956:3512]: Threading:WIN32 SSL:ENGINE
Sockets:SELECT,IPv6
2006.06.14 03:17:15 LOG5[3956:3600]: No limit detected for the number of
clients
2006.06.14 03:17:15 LOG7[3956:3600]: FD 172 in non-blocking mode
2006.06.14 03:17:15 LOG7[3956:3600]: SO_REUSEADDR option set on accept
socket
2006.06.14 03:17:15 LOG7[3956:3600]: gmail-pop3s bound to 127.0.0.1:1100
2006.06.14 03:17:15 LOG7[3956:3600]: FD 180 in non-blocking mode
2006.06.14 03:17:15 LOG7[3956:3600]: SO_REUSEADDR option set on accept
socket
2006.06.14 03:17:15 LOG7[3956:3600]: gmail-smtps bound to 127.0.0.1:250

....# info about other mail connections

2006.06.14 03:17:26 LOG7[3956:3600]: gmail-smtps accepted FD=236 from
127.0.0.1:3665
2006.06.14 03:17:26 LOG7[3956:3600]: Creating a new thread
2006.06.14 03:17:26 LOG7[3956:3600]: New thread created
2006.06.14 03:17:26 LOG7[3956:2812]: gmail-smtps started
2006.06.14 03:17:26 LOG7[3956:2812]: FD 236 in non-blocking mode
2006.06.14 03:17:26 LOG7[3956:2812]: TCP_NODELAY option set on local socket
2006.06.14 03:17:26 LOG5[3956:2812]: gmail-smtps connected from
127.0.0.1:3665
2006.06.14 03:17:26 LOG7[3956:2812]: FD 268 in non-blocking mode
2006.06.14 03:17:26 LOG7[3956:2812]: gmail-smtps connecting
64.233.167.111:587
2006.06.14 03:17:26 LOG7[3956:2812]: connect_wait: waiting 10 seconds
2006.06.14 03:17:26 LOG7[3956:2812]: connect_wait: connected
2006.06.14 03:17:26 LOG7[3956:2812]: Remote FD=268 initialized
2006.06.14 03:17:26 LOG7[3956:2812]: TCP_NODELAY option set on remote socket
2006.06.14 03:17:26 LOG5[3956:2812]: Negotiations for smtp (client side)
started
2006.06.14 03:17:26 LOG7[3956:2812]:  <- 220 mx.gmail.com ESMTP
w66sm450524pyw
2006.06.14 03:17:26 LOG7[3956:2812]:  -> 220 mx.gmail.com ESMTP
w66sm450524pyw

<logfile ends>

What mistake am I making?

Fortunately it seems that gmail supports SMTP over SSL too
(smtp.gmail.com:465) and I am using that. However I am also facing this
problem with another account which unfortunately allows SMTP only over TLS.

Thanks,
Shatadal.



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