Message transfer agent
A mail transfer agent or message transport agent ( MTA) is the software of a mail server that accepts e- mails and sends.
MTAs communicate very often after the Simple Mail Transfer Protocol, but also according to X.400. The MTA of the recipient is working with the Mail Delivery Agent of the mail server, which delivers the e -mails in the appropriate mailboxes. Here, the Local Mail Transfer Protocol are used. If a mail server is configured as an SMTP relay, it can also consist of an MTA.
One major component of MTA is its queue. There he collects orders, especially when the MTA of the recipient is not immediately accessible. In this case, he goes several times by the MX resource records of the recipient in order to process the order. If this fails, it sends a message back to the sender that his e -mail could not be delivered.
The MTA is the part of a mail server that can be attacked the most. He is also the component that the offer be measures to prevent spam.
Stand-alone MTAs
- Mail Transfer Agent