IMail Processing Order

Incoming mail addressed to a valid local address is processed in the following order.

  1. SMTP Access Control. The SMTPD service checks if the connecting IP is listed in the Access Control dialog box. If it is listed in deny access list, the connection is denied. If it is listed in the grant access list, the connection is allowed and processing continues.
  2. SMTP Kill File. The SMTP service checks if the email address listed in the "Mail FROM" address command to see if it is listed in the Kill List.. If the address or domain present, the SMTP service returns an error to the connecting client and does not accept the message. If no match is found, the SMTP service accepts the message.
  3. Connection Filtering (DNS Black Lists). If you have DNS Black Lists enabled, IMail compares the connecting IP address to the black lists to determine if a match occurs. If a match occurs, the email may be deleted (depending on the DNS Black Lists configuration) or an X-Header may be added and processing continues.
  4. Verification Tests. If you have the verification tests enabled, they verify the "Mail FROM" address, the HELO/EHLO domain, and perform a reverse DNS lookup. If any of these checks fail, the email may be deleted (depending on the configuration) or an X-Header may be added and processing continues.
  5. Sender Policy Framework (SPF). If you have the SPF feature enabled, it provides increased capability to stop incoming email from forged email addresses. Using a sender authentication scheme, a domain owner requires that legitimate messages from a domain must meet certain SPF criteria. Messages that do not meet the criteria are not accepted as a legitimate email message and are processed according to the SPF options selected on the SPF tab.
  6. IMail Anti-Virus. If you have IMail Anti-Virus installed, it checks the message for infected files or code. If infected, the mail is repaired, bounced, redirected, or deleted, according to the settings on the Anti-Virus tab. If the file is not infected, content filtering attempts to identify whether the message is spam .
  7. Premium AntiSpam. If you have the optional Premium Antispam filter installed, it provides automated spam protection in addition to the Standard Antispam filter included in IMail. Premium Antispam filter settings are applied before Standard Antispam filter settings.
  8. Content Filtering. If you have content filtering enabled, it determines if the message is likely to be spam. If the message is determined to be spam, it is either deleted, sent to the specified address, or an X-Header is inserted. If the message is not spam, aliases are checked.
  9. Alias. IMail Server checks to see if the addressee matches an alias in the destination domain. An alias is considered to be any of the following: standard alias, group alias, program alias, pager alias, beeper alias, fax alias, or a list-server mailing list name.
    • If there is a match to a program, beeper, pager, or fax alias, IMail Server executes the program or activates the beeper, pager, or fax.
    • If there is a match to a standard or group alias, IMai Server resolves the alias to the appropriate user ID(s), and checks the user ID.
    • If there is a match to a list-server mailing list name, IMai Server (a) processes the mail according to the settings for that list, and (b) checks the user IDs specified in the list settings.
    • If no match to any alias, IMail Server checks the user ID.
  10. User ID. IMail Server determines if the user ID is valid for the destination domain. If invalid, the mail is returned to the sender. If valid, the delivery rules for a list-server mailing list are checked.
  11. Delivery Rules for a list-server mailing list. If the message matches the rule criteria for a list, delivery follows according to the rule. If not, then the message is sent to the list server. If the message is not addressed to a list, Forwarding is checked.
  12. Delivery rules for the host. IMail Server determines if the message matches a rule for the mail host. If so, delivery follows according to that rule. If not, then rules for the user ID are checked.
  13. Delivery rules for the user ID. IMail Server determines if the message matches rule criteria for the user ID. If the message matches rule criteria for a user ID, then delivery follows according to the rule. If not, then Info Manager is checked.Forwarding. IMail Server determines whether an address is present in the Forward box on the General tab for this account. If so, IMail Server forwards the mail. If not, the mail is delivered to the user ID according to the established delivery rules.
  14. Info Manager. IMail Server determines whether the user ID has the Info Manager enabled. If so, the automatic response is sent and the message is delivered to either the forwarding address or (if no forwarding address) to the sub-area or mailbox specified. If the Info Manager is not enabled for this user ID, the vacation setting is checked as described in the next step.
  15. Vacation. IMail Server determines whether the user ID has a vacation message enabled. If so, the vacation message is sent. If not, the message is delivered to the User ID.