UW’s Strengths

UW imapd is at once both a kit of sorts and a completely self-contained IMAP server. By kit, we mean that there are adequate mechanisms built into UW IMAP to extend it to use virtually any kind of mailbox or authentication scheme, often with only a relinking required. By self-contained, we mean that it already has support for most authentication and mailbox schemes you’re likely to want to use.

Flexibility

The UW server takes a very different approach than the Cyrus server to dealing with mailbox formats. Cyrus understands only one mailbox format. To access a Cyrus mailstore, you’re limited to access through the Cyrus server. The UW server, on the other hand, understands many different mailbox formats. It goes to great lengths to detect the format of an existing mailbox and work with it.

The flexibility in mailbox formats can be a major selling point for the UW server. Some sites have users who demand that mail be stored in standard Unix format so that it can be directly manipulated (e.g., with Unix tools like grep or with Unix mail clients like elm) without using IMAP. With the UW server, the site administrator has the option of leaving the mailstore open to direct access or locking it down to IMAP access only.

You may come across claims that the UW server doesn’t perform as well as Cyrus. Most performance comparisons of UW to Cyrus are comparing apples to oranges. The default UW IMAP installation uses traditional Unix mailbox format, where the mailbox is a ...

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