Mail retrieval agent
Encyclopedia
A mail retrieval agent (MRA) is a computer
application that retrieves or fetches e-mail
from a remote mail server and works with an 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
, getmail
and retchmail.
The concept of MRA is not a standardized in email architecture. Although they operate like mail transfer agent
s, MRAs are technically clients when they retrieve and submit messages.
run the mail retriever agent against each mail recipients user account.
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
application that retrieves or fetches e-mail
E-mail
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the...
from a remote mail server and works with an mail delivery agent
Mail delivery agent
A mail delivery agent or message delivery agent is a computer software component that is responsible for the delivery of e-mail messages to a local recipient's mailbox...
to deliver mail to a local or remote email mailbox
Email mailbox
An email box is the equivalent of a letter box for electronic mail. It is the destination where electronic mail messages are delivered.-Definitions:...
. MRAs may be external applications by themselves or be built into a bigger application like an MUA. Significant examples of standalone MRAs include fetchmail
Fetchmail
Fetchmail is an open source software utility for POSIX-compliant operating systems which is used to retrieve e-mail from a remote POP3, IMAP, ETRN or ODMR mail server to the user's local system. It was developed from the popclient program, written by Carl Harris.Its chief significance is perhaps...
, getmail
Getmail
getmail is a simple mail retrieval agent intended as a replacement for fetchmail, implemented in Python. It can retrieve mail from POP3, IMAP4 and Standard Dial-up POP3 Service servers, with or without SSL...
and retchmail.
The concept of MRA is not a standardized in email architecture. Although they operate like mail transfer agent
Mail transfer agent
Within Internet message handling services , a message transfer agent or mail transfer agent or mail relay is software that transfers electronic mail messages from one computer to another using a client–server application architecture...
s, 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 mboxMboxmbox is a generic term for a family of related file formats used for holding collections of electronic mail messages. All messages in an mbox mailbox are concatenated and stored as plain text in a single file...
formatted mailbox - Direct delivery to a maildirMaildirThe Maildir e-mail format is a common way of storing e-mail messages, where each message is kept in a separate file with a unique name, and each folder is a directory...
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 cronCron
Cron is a time-based job scheduler in Unix-like computer operating systems. Cron enables users to schedule jobs to run periodically at certain times or dates...
run the mail retriever agent against each mail recipients user account.
Examples
Examples of stand-alone MRAs include:- fdm (e-mail utility)Fdm (e-mail utility)fdm is a simple, lightweight replacement for mail fetch, filter and delivery programs such as fetchmail and procmail ....
- A combined mail retrieval agent and mail delivery agentMail delivery agentA mail delivery agent or message delivery agent is a computer software component that is responsible for the delivery of e-mail messages to a local recipient's mailbox... - fetchmailFetchmailFetchmail is an open source software utility for POSIX-compliant operating systems which is used to retrieve e-mail from a remote POP3, IMAP, ETRN or ODMR mail server to the user's local system. It was developed from the popclient program, written by Carl Harris.Its chief significance is perhaps...
- getmailGetmailgetmail is a simple mail retrieval agent intended as a replacement for fetchmail, implemented in Python. It can retrieve mail from POP3, IMAP4 and Standard Dial-up POP3 Service servers, with or without SSL...
- mpop
- retchmail