SMTP Satellites

Other LAN Systems

SMTP Satellites

Why?

• Systems inside our domain may not be an full MTA, but we still may want to allow them to send messages.

  • i.e. Log messages from database machine to be sent to our email address

• Run a very stripped down MTA on these hosts

• They will send messages to mail server

• Will not receive messages

• Mail server relays for satellites

SMTP Satellites

SMTP Satellites

• Mail satellite MTA's do NOT receive incoming messages.
• DNS directs mail traffic to mail server via MX records
• Mail server accepts incoming messages for satellite systems, storing them in users inbox.

SMTP Satellites Configuration Steps (Outgoing)

• On Satellite, install exim4, mailutils
• Configure exim4 to send through mailserver and NOT receive
• On mail server configure exim4 to RELAY for satellites

SMTP Satellites Configuration Steps (Incoming)

• On satellite, install exim4,
• configure NOT to receive
• On mail server, configure exim4 to treat satellite destinations as local
• On mail server configure exim4 to RECEIVE for satellites
• Configure DNS to have MX records for ALL satellite systems
• Configure DNS to have TXT spf records for ALL satellite systems
• Test!!!