[stunnel-users] Sending Email from PLC Without Authentication with gmail

Stephen Gates sgates at hkscholz.com
Wed Jun 26 21:25:25 CEST 2013

A customer needs to send emails from a Programmable Logic Controller (PLC)
which cannot provide authentication. The customer's email server is gmail
which obviously requires authentication. 


The PLC IP is and the PC IP on which stunnel is installed is


My config is: 


cert = stunnel.pem


client = yes

accept = 25

connect = smtp.gmail.com:465


The PLC is set up to send emails to the IP of the PC


When I try to send emails I get the following in the stunnel log:


2013.06.26 14:26:30 LOG5[12384:13048]: Service [smtps] accepted connection

2013.06.26 14:26:30 LOG5[12384:13048]: connect_blocking: connected

2013.06.26 14:26:30 LOG5[12384:13048]: Service [smtps] connected remote
server from


Any help would be greatly appreciated!


Stephen Gates

Harold K. Scholz Company

7800 Serum Avenue

Ralston, NE  68127



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.stunnel.org/pipermail/stunnel-users/attachments/20130626/73aed221/attachment.html>

More information about the stunnel-users mailing list