Microsoft Exchange 2003 - Types of Recipients

http://www.computerperformance.co.uk/exchange2003/exchange2003_recipients.htm

Understanding the Recipient Types in Microsoft Exchange 2003

There is no doubt, knowledge is power. If you truly understand the names and capabilities of email objects, then you will always choose the right recipient for the right job.

Mailbox enabled user - Standard email account in Exchange Server 2003. A regular Active Directory user with a full MAPI mailbox. (90% of all email accounts are this type.)

Mail-enabled user - Tricky recipient. An Active Directory account with an email address, but no mailbox in your Exchange Organization. I call this the contractor object. Their email is delivered, not to your exchange mailstore, but to their external account, e.g. hotmail or gmail.

Distribution Group - The old Exchange 5.5 DL (distribution list). Big organizations may favour the Universal Distribution groups, while companies with one domain prefer Global Distribution groups.

Query-based Distribution Groups - A great new idea in Exchange 2003. You must investigate these dynamic groups which are populated by LDAP queries. See how to manage these Query-based Distribution Groups groups here.

Security Enabled Group - Where ever possible, avoid this object and use Distribution Groups instead.

Here is my reasoning for shunning Security Enabled Groups for email recipients. Technically it takes longer to logon if users are members of lots of Security Groups - SIDS have to be checked and Universal group membership has to be verified.

However my main objection is because security groups are normally used for share permissions. I once saw an administrator add a user to a group that had access to the printer. What they forgot was that this was a mail-enabled group and the new user started receiving emails that were not meant for their eyes. (It was unpleasant because they were emails about that person's redundancy.)