José P. Airosa's questions

I need to filter email delivery in Postfix based on a specific header.

Lets have the following example:

There's some PHP script that will dispatch emails to the local MTA (postfix). These emails contain a specific custom header (for example sake, X-EMAIL-TYPE) that will have one of 3 values:

• Bulk
• Transactional
• Autoreply

I need to dispatch emails to different SMTP servers based on the X-EMAIL-TYPE header.

Is this possible in Postfix? If yes, how can I do this?

Thank you!

I'm in the process of configuring an email platform and I would like to clear some doubts that I have.

When building this system I have 2 options:

1. Have PHP doing the connections to my SMTP external server (it's a delivery only server). This is how my network is configured at the moment and I feel it's very heavy on the server.
2. Have PHP connecting to my local MTA and having the local MTA (Postfix) connecting through SMTP to my external delivery server

I think the option 2 is the preferable one for a couple of reasons:

• Dispatch from the email platform is faster
• PHP processes will finish faster
• Delivery itself will be on Postfix (local MTA) responsibility thus creating a new layer on the delivery data flow providing a lot more abstraction on the PHP platform
• Delivery rules can be defined specifically on Postfix

So, question 1 is if this is the preferable solution or if I should keep option 1?

Bellow is a small representation of what I'm referring in point 2:

                                                                  +------------+
                                                                  |            |
                              +---> smtp external backend a ----->|            |
                              |                                   |            |
platform -------> local MTA lb ---> smtp external backend b ----->|  Delivery  |
                              |                                   |            |
                              +---> smtp external backend c ----->|            |
                                                                  |            |
                                                                  +------------+

Question 2:

If this is the preferable situation how can I create a load balance Postfix solution?

I need to be able to easily add and remove SMTP servers.