Yes, it works !! Thank you very very much. 1. save the Rebol source code in the link 'ssmtp' through the web page Graham provided above. Save to prot-ssmtp.r 2. save the Rebol source code in the link 'ssend' through the web page Graham provided above. Save to prot-ssend.r 3. run this , do %prot-ssmtp.r do %prot-ssend.r set-net [ myaccount@gmail.com smtp.gmail.com none none none none myaccount@gmail.com "mypassword" ] <==== edit this line ssend friend@emailaddress.com "Hello ... test message" 4. it works !! if use ISP's Internet connection. But if use my company's office network it makes an error : ** Access Error: Cannot connect to smtp.gmail.com ** Where: open-proto ** Near: smtp-port: open [scheme: 'ssmtp] either only Because necessary ports are blocked by our MIS I believe. So, Rebol program can send email through gmail easily. I hope Google will index this thread soon. There's no clear answer like this on the net so far.