Master server vs. slave server

Question

What does the master server do vs. just a normal server?

Answer

Master server:

  • hosts frontend application (CrossBox client)
  • proxies IMAP/SMTP/POP3 traffic to the correct slave (CrossBox MailProxify)
  • enables one webmail/IMAP/SMTP/POP3 hostname for all users (no matter on what slave they are actually hosted)
  • routes logins to the correct slave
  • forwards backend/frontend updates to slaves
  • delivers updates to iOS/Android users

Slave server:

  • hosts backend (CrossBox server) and other services for accounts on that server
  • stores data (emails, files, databases) for accounts on that server
  • does all work for accounts on that server