Mail retrieval agent

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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.[citation needed] MRAs may be external applications by themselves or be built into a bigger application like an MUA. Significant examples of standalone MRAs include fetchmail, getmail and retchmail.[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[edit]

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[edit]

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.


Examples of stand-alone MRAs include:

See also[edit]