Title: Plan email for an organization
Course: CIS 208: Linux/UNIX III: Intermediate System Administration, Networking, and Security ~ For IGNITE Review > Section: Learning Modules

Plan email for an organization

There are several things to consider when planning how to manage email for an organization.

- The first is to determine which DNS domains will be supported for incoming email.  It is common for companies to have several domains, and email will need to be accepted and processed for each of them.  Also it is common to select one primary domain, so that all email sent to any of the domains arrives in a single inbox on a single server.  It will be necessary to plan hostnames, IP addresses, MX records, A records and pointer records for each of the domains.  SSL certificates may need to be generated or purchased.  Also a "smarthost" or outbound relay may be desired or required.
- The next decision is how and where the mail services will be hosted.
  - If integrated calendar and contact features are required, it may be necessary to go with Zimbra, Exchange or a hosted service such as Gmail.
  - If privacy and security are essential, sendmail or postfix are excellent choices.  The incoming mail servers can be hosted internally in a DMZ or on a Virtual Private Server provided by a hosting company.
  - Consider if special archiving is required, since some organizations are required by law to keep archival copies of all email sent and received for a period of 7 years or more.  The choice of how and where to host email services can be complex.
  - If the organization decides to host their server, there are many options including sendmail, postfix, qmail and Zimbra.
  - In addition, they may choose to have a dedicated mail relay to handle incoming mail in the DMZ with the server for client connections inside the protected LAN.  Top rated mail servers support smtp, pop and imap, and some include web clients such as SquirrelMail.  SSL and/or TLS encryption needs to be supported for all connections over the Internet.  The main server will need to have enough disk space to store the users' inboxes and other folders.  Typically inboxes are located in /var/mail or /var/spool/mail, while other folders are stored in the users' home directories.  Consider having separate partitions for these directories and using quotas to ensure that no one user can accidentally fill a filesystem.
  - If a separate relay server is desired, plan to filter incoming email on this server.  This will lighten the load on the main server and will prevent unwanted email from being delivered, thus reducing the number of messages that are archived.  Since email will be relayed for delivery, but not delivered, there will not be a requirement for extended disk space for user folders.
- Plan a standard method for user account names.  Many organizations use a first initial and last name, but this can lead to confusion when several users could be assigned the same email address.  Make a list of dummy accounts such as "info", "help", "sales" and "staff" which will either go into a separate account or be forwarded to one or more individuals.