Receiving Email
This is the same diagram from last week:
Last week we've set up Postfix on VM2. Postfix is an MTA, a.k.a. an SMTP server. Last week we've set it up for sending email (it was mostly the default setup) and this week we'll set it up to receive email.
We'll start with the same Postfix service on the same machine, we'll add an LDA (dovecot-lda) and test to make sure it works.
Finally we'll set up an IMAP server (Dovecot) so you can read your email from an MUA such as Thunderbird or a Webmail (we'll set up webmail in the Apache lab).
MX Record
If you haven't already done it - set up an MX record in your DNS server to make vm2.yoursenecaid.org the server responsible for receiving emails for anyuser@yoursenecaid.org
MTA and LDA for Receiving Email
Postfix is capable of performing the function of an LDA but it has limited configurability, and is generally not used for that purpose. Currently the most popular LDA is LMTP but we'll use dovecot-lda because it's also pretty popular and we'll later be setting up Dovecot as an IMAP server. Using the two as a pair will increase the performance of your IMAP server.
Edit your /etc/postfix/main.cf file and scroll down to (or search for) mailbox_command. Add the following line:
mailbox_command = /usr/libexec/dovecot/dovecot-lda -f "$SENDER" -a "$RECIPIENT"
Don't replace any variables, those are set automatically by Postfix when it runs the LDA. If you're interested - you can read about dovecot-lda here and here but it's not required reading.
If you look - you'll see that dovecot-lda doesn't exist yet. Install the dovecot package - that will come with dovecot-lda.
Don't forget to restart your postfix service.