Every company or organization that handles email must be protected by a firewall, so every email sent to a mailing list passes through a firewall where it is screened by virus and spam filters. As mentioned, anything caught by the spam filter is automatically deleted without any notification being generated. If the message contains a virused email attachment, the email is deleted, but the sender is warned. If the email passes the tests for malware and spam, it is sent to the mailing list where it may face further screening.

Once a message to be posted arrives at a mailing list, it is subject to rules that control posting. These rules frequently limit direct posting access to the higher levels of list users, such as subscribers or even moderators only. On the most restrictive lists, even moderator's posts are moderated. The software determines the sender's identity based on the sender's email address, looking for the email address on it's lists. It determines what kind of list user the sender is based on which list the email address is on, then applies the rules that apply to that level of list user. Depending on the list rules, the message may be routed directly to the list, to the moderation queue or the list may reject it outright.

Posting access control is somewhat complex, so there are several help documents that delve into this subject. If you aren't familiar with user levels (and why the mailing list thinks you are your email address), see List User Levels and Access Control. To learn more how moderated lists work, see Moderation.

The way posts are routed is partly dependent on list rules and configuration. List may may be unmoderated, send all posts for moderation, or moderate public posts and allow subscribers, posters and moderators to post directly. If the list is unmoderated, public posts may be rejected, while other users messages are posted directly. If the list is moderated, posts from everyone except moderators may be rejected.

List email has certain features that distinguish it from email correspondence sent directly from person to person. Before a message is distributed to the list, the mailing list resets the information in certain fields. List email has these distinguishing features:

The Kavi Mailing List Manager maintains a set of four subscriber lists (i.e., Regular Subscriber, Digest Subscriber, Poster and Moderator). Depending on list configuration, people may be able to subscribe and unsubscribe to these lists via email. Public lists generally support this feature for all subscribers except moderators, who can only subscribe and unsubscribe through the Web tools for security reasons. People aren't allowed to subscribe to the Poster List, either, but if configuration allows, moderators can add posters via email, or subscribers can be added automatically or by administrators through Admin tools. Private lists tend not to accept subscribe and unsubscribe requests via email, forcing all subscription actions to be performed through the Kavi Mailing List Manager tools for the added security provided by authentication.

When an individual is subscribed through Kavi Mailing List Manager tools, the primary email address is pulled from the Kavi® Members database. If the list is configured to use a Poster List and an alternate email address is stored in the database, the alternate email address is automatically added to the Poster List. If the subscriber's email address is changed through the Edit an Email Address tool, the Kavi Members database will be updated, and the address will be updated on all lists to which it is subscribed.

If a mailing list accepts subscription requests via email, users can subscribe and unsubscribe themselves directly to the Regular Subscriber and Digest Subscriber lists. Lists that accept email subscription requests may be configured to accept public requests (i.e., from unknown addresses), or may only accept requests from subscribers (i.e., from addresses on the Regular or Digest subscriber lists).

These lists are managed by ezmlm, and the information in these lists is propagated to the Kavi Members database by periodic automatic or manual database synchronization operations. See the page help for the Synchronize Lists tool for more information.

Since the Kavi Mailing List Manager only recognizes email addresses, a subscriber's record in the Kavi Members database can only be located and updated if a subscriber submits an email subscription request from an address that appears in the Kavi Members database. This means that an individual in the Kavi Members database must send email subscription requests from their primary or alternate email address (assuming the Web site collects alternate addresses) to be properly identified and have their updated subscription information associated with their personal record. If the individual subscribes via email under an unknown address, the software has no way of connecting the subscription with the individual's database record. As far as the software is concerned, any unknown address on its subscriber lists is classified as a public subscriber.

This means that some of the public subscribers on lists that accept email subscription requests from the public actually belong to members who have subscribed under email addresses that aren't in the Kavi Members database. Because the subscribed address isn't connected with the individual, the subscription won't be accessible through User tools, and any updates performed on the individual's primary or secondary email address in the database won't be propagated to any list subscriptions where the individual is subscribed as a public user. Likewise, any updates to the addresses associated with the public subscriptions won't affect the primary or secondary email addresses in the Kavi Members database.