All About Email - Definition of Email by Merriam-Webster

Return-Path: after the delivery SMTP server makes the last shipment of a message, it inserts this field at the top of the header. Other fields added on top of the header by the getting server may be called trace fields. Authentication-Results: after a server confirms authentication, it can save the lead to this field for consumption by downstream representatives.

DKIM-Signature: stores outcomes of Domain, Keys Identified Mail (DKIM) decryption to confirm the message was not altered after it was sent. Auto-Submitted: is used to mark automatic-generated messages. VBR-Info: claims VBR whitelisting Message body Material encoding Internet email was created for 7-bit ASCII. Most e-mail software is 8-bit clean, but must presume it will communicate with 7-bit servers and mail readers.

The 8BITMIME and BINARY extensions were introduced to allow transmission of mail without the requirement for these encodings, however many mail transport agents might not support them. In some nations, e-mail software violates 5322 by sending out raw non-ASCII text and numerous encoding plans co-exist; as a result, by default, the message in a non-Latin alphabet language appears in non-readable form (the just exception is a coincidence if the sender and receiver utilize the same encoding scheme).

HTML e-mail messages often consist of an automatic-generated plain text copy for compatibility. Russ-Parry.com of HTML consist of the ability to include in-line links and images, set apart previous messages in block quotes, cover naturally on any screen, usage emphasis such as underlines and italics, and change typeface styles. Downsides consist of the increased size of the email, privacy issues about web bugs, abuse of HTML email as a vector for phishing attacks and the spread of destructive software application.

Some Microsoft e-mail clients may permit abundant format utilizing their proprietary Rich Text Format (RTF), but this must be avoided unless the recipient is ensured to have a compatible email customer. Servers and customer applications Messages are exchanged in between hosts using the Simple Mail Transfer Protocol with software application called mail transfer agents (MTAs); and provided to a mail store by programs called mail delivery representatives (MDAs, also in some cases called regional shipment representatives, LDAs).