Example of a Typical Multiserver Configuration The exact configuration for each deployment is highly dependent on variables including the number of mailboxes, mailbox quotas, performance requirements, existing network infrastructure, IT policies, security requirments, spam filtering requirements, and so forth. The figure below shows a typical configuration with incoming traffic and user connection. Typical Configuration with Incoming Traffic and User Connections 1 Inbound Internet mail goes through a firewall and load balancing to the edge MTA for spam filtering. 2 The filtered mail then goes through a second load balancer. 3 An external user connecting to the messaging server also goes through a firewall to the second load balancer. 4 The inbound Internet mail goes to any of the Zimbra MTA servers and goes through spam and virus filtering. 5 The designated Zimbra MTA server looks up the addressee’s directory information from the Zimbra LDAP replica server. 6 After obtaining the user’s information from the Zimbra LDAP server, the MTA server sends the mail to the appropriate Zimbra mailbox server. 7 Internal end-user connections are made directly to any Zimbra mailbox server, which then obtains the user’s directory information from Zimbra LDAP and redirects the user as needed. 8 Server backup can be processed to a mounted disk.
