I have had to transfer one of my sites over to a virtual server on a cloud provider from a shared host. I was planning on leaving the mailboxes on the shared host and just using the cloud for the website. The website is up an running on the server, but is not sending mail.
Postfix is installed and configured as per this question. When I send an email from PHP, including the from address in the headers, it ends up sitting in the postfix queue and staying there. The senders address has also changed to the apache username. My question is how do I configure postfix so that I can send an email, using any from address specified in the PHP script.
My server has a static IP, and the firewall is blocking incoming ports except for 22, 80 and 443.
EDIT: The emails are stuck in the queue with a "connection timed out" message. Further investigation reveals that I cannot telnet into any other mail server on port 25. I have logged a ticket with the cloud provider to get that sorted out.