From: Mario on
Every time a named property is created within a mailbox database event 9873
is fired:

Event Type: Information
Event Source: MSExchangeIS
Event Category: General
Event ID: 9873
Date: 1/29/2010
Time: 11:22:32 AM
User: N/A
Computer: ExchangeServerName
A named property has been created for the database "/o=Company
AG/ou=Exchange Administrative Group
Private MDB".
ID: 0x9954
Named property GUID: 00020386-0000-0000-c000-000000000046
Named property name/ID: x-host
The following user is attempting to create the named property: "Firstname
Protocol: MAPI
Client type: User
Client version: 11.0.8200.0

I have seen three different client types (field "client type"):
- Transport
- User
- Administrator

My question is, what is the difference between those three client types?
What is the difference betwenn "Administrator" and "User"?