I'm doing development for a webapp that sends emails out to users. I've typically used Argosoft Mail Server (Freeware) in a windows environment as an SMTP server in which I've enabled relay but shutdown actual delivery. This allow me to point my webapp to my local server, and am able to validate all emails that are sent out by looking at the outgoing queue. Additionally, to be 100% safe, I would put in a non-existant DNS server to use to ensure that if I ever accidentally enable delivery, the server would still not be able to look up any external addresses and deliver the mail.
Now that I am doing development on an OSX machine, I'm looking for a similar solution. By default, OSX comes with Postfix installed, so I figured I would just use that and configure it similarly. However, I cannot seem to find an option anywhere to disable all outgoing email. Essentially, I want to set up Postfix as an open relay server, but disable delivery of all email. I can then look at the outgoing queue and see if the email(s) are as expected.
Is there anyway to easily accomplish this? Or is there a better solution I can use?