Received emails from remote IP addresses and store them in a folder for processing

[Simon.M]

Hello

I hope you are doing well. I am VERY NEW to PostFix.

I have a question and I am going round and round in a circle. I would like to be able to accept all emails coming from remote IP addresses. When the email is received, I need PostFix to inform the sending SMTP server that the email has been successfully received and then store the email received to a predefined folder on the server.

I then am going to write a tool to action that email and modify it to meet my needs. Once it is modified accordingly, I would like to send the email back to PostFix to delivery / relay the email onwards. For each domain I relay the email to, I would like to be able to specify the DNS name where the email must be relayed based on the domain name of the recipient.

Is this possible with PostFix? I have been told it is. I have managed to receive the email on the PostFix server and store it. However, it then relays the email immediately onto the recipient's server without me actioning it yet. I did specify the domain and the DNS server it must go to in the /etc/postfix/transport. I will obviously build this transport listing up over time.

Any assistance would be greatly appreciated! I have spent two days at this now and I am starting to test my sanity levels!

Regards,
Simon