Red Hat System Administration III - Unit 14 - Basic SMTP Configuration

• MTA (Mail Transfer Agent) - relay mail from point to point until it's delivered.
• MDA (Mail Delivery Agent) - deliver mail to recipients local message store. Postfix provised its own MDA to deliver to default local file-based message store: /usr/libexec/postfix/local
• MUA (Mail User Agent) - clients used to send email and read email in user's message.

Key concept

• Relaying - forward from server to server
• Queueing - queued and retrieved periodically by MTA
• Rejected - failed at our end
• Bounced - rejected at their end

Postfix

• Use postconf to see all the available Postfix options

• To make Postfix available on all interfaces, set inet_interfaces

  > postconf -e inet_interfaces=all
  

• mutt is a mail client for terminal

• postfix flush can clear mail out of mail server for sending
• /var/spool/mail/$USER is where a user's mail store is

Intranet Configuration

• Standard roles:
  • null client -- runs local MTA, so all email can be forwarded to a central mail server for delivery. Does not accept local delivery for any email messages. Most machines will be null clients.
  • inbound
  • outbound

Postfix Configuration

• inet_interfaces - which interfaces to listen on
• myorigin - usually company domain
• relayhost - outbound mail server
• mydestination - company domain on inbound server
  • relevant for inbound!
• local_transport - for the MDA to put it in the directory
• mynetworks - (relay from) use for outgoing mail server
  • relevant for outbound!
• Run man postconf for more info

Aliases

• Configure an alias for andrew called acctmgr

  > vi /etc/aliases
  + acctmgr: andrew
  > newaliases
  

• Questions to answer:

  • Configure your "MTA" mail server according to the following requirements:
    • Your mail server should accept the mail from remote hosts as well as localhost
      • set mydestination to accept mail for localhost, $myhostname, $mydomain, example.com