I am not a Php developer, however some of my clients PHP based scripts to generate emails get refused by various smtp relays, responding with links to http://cr.yp.to/docs/smtplf.html
I understand the problem, but my question in short, is What is the best way to fix this issue?
Does the latest version of PHP fix this issue? We are running a slightly older version. Whilst some clients can probably edit their scripts directly, others may be using scripts like phpbb, which they cannot address.