Adding STARTTLS functionality to outbound SMTP sessions via iRule

I have recently also been trying to do the same, server side STARTTLS and SSL only, not clientside, and found this article a month or so ago. I managed to use your irule suggestions to get it working on mine as well.

I had to make some adjustments to the EHLO message, to add a server name on the end, otherwise the other end refused to start the TLS handshake (SERVER HELLO error), and also had to tweak the if statements to match some different response strings from the other side. But otherwise it works well.

Here is my devcentral post on the same thing, were i have posted my version of the irule:

https://devcentral.f5.com/questions/need-an-irule-for-starttls-for-smtps-server-side-only-not-client-side

If you've learned any other lessons using this irule since and have any further advice then let me know. As far as i can tell, even 11.6.0 still doesn't allow you do configure STARTTLS for the Serverside in the GUI or config files, and irule still seems to be the only way. Hopefully they will improve this in later versions.