What is MDA (fetchmail) and MTA (sendmail)?
Solution 1:
MTA - Mail Transfer Agent - sends and receives email between MTAs and among other elements of an email system
- Postfix
- Sendmail
- Exim
MDA - Mail Delivery Agent - receives email from an MTA for delivery to a mailbox
- procmail
- dovecot
- Courier
MUA - Mail User Agent - email client
- Thunderbird
- elm
- Exchange
Here is an overview of how the elements interact.
Solution 2:
when you are talk about mta -it is mail server side role;
when you are using apple mail - it is client, and use smpt/pop3/imap/or other client protocols, but i think it is not mta or mda