As part of my app’s config process, I have a sanity checker that validates all user-supplied data. This includes email server settings that the app uses to send email.
I’d like a simple sanity check on those settings without actually sending any email. It’d be great if this could support all standard flavors of SMTP setups including those with authentication/ssl/etc.
It doesn’t need to be exhaustive but the more coverage, the better.
Currently all I do is verify I can open a connection to the given server on the given port. Something a little deeper would be nice.
Note: I’m not trying to validate email addresses–that’s not relevant to this question.
You just open a raw connection to the server & port that the user supplies and do a
to see if you get a valid HELO response & Sender OK Response (if smtp authentication is enabled).
Same as you would do if you telnet direct to the server.
http://www.petri.co.il/test_smtp_service.htm
This might also be useful
http://qmail.jms1.net/test-auth.shtml