What is the protocol that is used to send emails? - email

What is the protocol that is used to send emails from one server #example.com to another #example2.com

It's Simple Mail Transfer Protocol, commonly known as SMTP. It was first defined in RFC 812, but there are more recent enhancements.

Related

Why does the SMTP explicitly provide for relaying?

The third paragraph of the Simple Mail Transfer Protocol RFC states that
An important feature of SMTP is its capability to transport mail
across multiple networks, [...] Using
SMTP, a process can transfer mail to another process on the same
network or to some other network via a relay or gateway process
accessible to both networks.
Do IP/DNS, on which SMTP relies via TCP, not already provide these features? Why does SMTP re-implement them instead of, say, letting the sender directly TCP-connect to the destination mail server?

How are emails sent when using for example Outlook Web access (OWA)

Nowadays it is also possible to access Emails on the web. The web protocol is Https or just plan Http .
But as everyone learnt emails use protocols like Pop3, Smtp or Imap .
So on the web will there still be used e.g. SMTP to send an email ??
If yes, how will it work. Will the smtp protocol be embedded in the http protocol the same way e.g. SOAP is embedded in http.
Thanks.
As you said, for sending mails the SMTP protocol is used. The server you are accessing via HTTP(S) when using for example OWA will handling this protocol for you.
Basically you as a client using OWA will tell the server (MS Exchange) to send a mail. But the communication between you two is using the HTTP(S) protocol. And as a result of your communication the Exchange Server will use the SMTP protocol as a client to issuing the sending of your email.

Can I send a mail on behalf of someone else using mail API?

Does the mail API (regardless of the programming language) allow to send mails on behalf of any arbitrary email address?
to understand what I mean, go here http://eyhosting.com/client_data/greatermedical/recform.php?item=comsu3397.html
And enter in the *your email: any arbitrary mail such as stevejobs#apple.com ... and in the *email 1: box enter your email .. Then watch your mail inbox.
Yes an email address specifies those to, from, attachments, etc fields in the header.
There is no universal mail API. But yes, it is possible (and even easy) to send mail and spoof the sender's address, for legitimate and less-than-legitimate reasons.
SMTP is the email protocol. See RFC 821, RFC 822, RFC 2821, and RFC 2822. While depending on the version of the protocol, the syntax changes slightly, the receiving server always trusts the from address that the sending client specifies. While there are other protocols which do perform sender identification and header overwriting, such as Exchange, these are in the minority.

What protocol does MFMailComposer use to send mail?

What protocol apple has used to send mail through MFMailComposer?SMTP or other Protocol?
any help please?
The mail composed using MFMailComposer is sent just as regular e-mail composed in the Mail application. In other words it’s SMTP.
If uses your default mail settings. If you have set your default mail account as Microsoft Exchange, it will use that, and if it is SMTP (with our without SSL), that will be used.
Generally while using MFMailComposer, you don't need to worry about the protocol. If the default mail account is set properly, the mail can be sent.

phonenumber#operator.com - How do they do it?

In this question, Codygman gave an answer that some operators offer a way to send an SMS by sending an email to phonenumber#operator.com. I am curious about the technical solution behind that. I doubt they have a mailbox for every phone number.
Is there anyone out there who has a clue how they do it?
Email on the internet operates on the SMTP protocol. Standard MTAs (mail transport agents) will deliver messages to static mailboxes.
All the above solution requires is a custom MTA that instead of delivering to static mailboxes it interprets the username part of the address as a phone number and then pipes the request to an SMS gateway.
Certain mail software might be configurable enough such that this won't even require custom software and can be done with straight configuration.