RFC 2193 (rfc2193) - Page 1 of 9
IMAP4 Mailbox Referrals
Alternative Format: Original Text Document
Network Working Group M. Gahrns
Request for Comments: 2193 Microsoft
Category: Standards Track September 1997
IMAP4 Mailbox Referrals
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
1. Abstract
When dealing with large amounts of users, messages and geographically
dispersed IMAP4 [RFC-2060] servers, it is often desirable to
distribute messages amongst different servers within an organization.
For example an administrator may choose to store user's personal
mailboxes on a local IMAP4 server, while storing shared mailboxes
remotely on another server. This type of configuration is common
when it is uneconomical to store all data centrally due to limited
bandwidth or disk resources.
Mailbox referrals allow clients to seamlessly access mailboxes that
are distributed across several IMAP4 servers.
A referral mechanism can provide efficiencies over the alternative
"proxy method", in which the local IMAP4 server contacts the remote
server on behalf of the client, and then transfers the data from the
remote server to itself, and then on to the client. The referral
mechanism's direct client connection to the remote server is often a
more efficient use of bandwidth, and does not require the local
server to impersonate the client when authenticating to the remote
server.
2. Conventions used in this document
In examples, "C:" and "S:" indicate lines sent by the client and
server respectively.
A home server, is an IMAP4 server that contains the user's inbox.
A remote mailbox is a mailbox that is not hosted on the user's home
server.
Gahrns Standards Track