Mail retrieval agent
A mail retrieval agent (MRA) is a computer application that retrieves or fetches e-mail from a remote mail server and works with a mail delivery agent to deliver mail to a local or remote email mailbox. MRAs may be external applications by themselves or be built into a bigger application like an MUA. Significant examples of standalone MRAs include fetchmail and getmail.[1]
The concept of an MRA is not standardized in email architecture. Although they operate like mail transfer agents, MRAs are technically clients when they retrieve and submit messages.
Delivery mechanisms
The mail retrieval agent may support delivery of retrieved mail via the following mechanisms:
- Via a mail transport agent (Listening for SMTP transfers on port 25)
- Via a mail delivery agent
- Direct delivery to an mbox formatted mailbox
- Direct delivery to a maildir directory
- Output to standard output
Multiple mailbox support
The mail retriever agent may support retrieval of mail from multiple mailboxes simultaneously. This enables a mailserver to have a centrally configured mail retriever agent that runs against a dedicated mail system account and collects the mail for all users in a single invocation, rather than having the cron run the mail retriever agent against each mail recipients user account.
See also
References