 | This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages)
|
Mbox is a generic term for a family of related file formats used for holding collections of email messages. It was first implemented in Fifth Edition Unix.
All messages in an mbox mailbox are concatenated and stored as plain text in a single file. Each message starts with the four characters "From" followed by a space (the so-called "From_ line") and the sender's email address. RFC 4155 defines that a UTC timestamp follows after another separating space character.[1]
However, as noted in the RFC, there is enormous variation between different storage systems. As a specific example, if exporting via IMAP the popular Gmail service uses - as a placeholder in lieu of the sender's address, follows this with a timestamp representing either the time the IMAP export was configured or the time of reception (whichever is more recent), and makes no attempt to escape "From -" strings which appear in the body of an email.
A format similar to mbox is the MH Message Handling System. Other systems, such as Microsoft Exchange Server and the Cyrus IMAP server, store mailboxes in centralized databases managed by the mail system and not directly accessible by individual users. The maildir mailbox format is often cited as an alternative to the mbox format for networked email storage systems.
- ^ Hall, E., ed. (September 2005). "Request for Comments: 4155 – The application/mbox Media Type". Internet Engineering Task Force. Archived from the original on 17 May 2021. Retrieved 17 May 2021.