phpmail, sendmail and smtp- Logic

[eluser]nirbhab[/eluser]
Can tell me the difference between sendmail, phpmail function and smtp mail.
I just wanna clear my logics. I am confused among these three(which one to use and why, what are the basic features which would help me to decide, which one to use in which condition).
No Code please, just logic is required.

Hope i made my self clear.

[eluser]Seppo[/eluser]
They are different ways for sending the email... All of them are equally good, just use the one that works on your server...

Sendmail is a program.
SMTP will connect to a SMTP server to send it.
Native will you use your php defaults.

[eluser]nirbhab[/eluser]
If sendmail is a program, than what does sendmail_path /usr/sbin/sendmail -t -i does??
For more reference: http://www.nirbhab.com/phpinfo.php[search for sendmail_path]
Does it places a email-file on my linux server, so that my client could read it?

SMTP [with auth and without auth] two types exist in SMTP ????

Can native mail function be disallowed to send a plain/html format form server side?

If i have the phpinfo, than how could i determine that which one to use?

[eluser]Seppo[/eluser]
I do not know how sendmail works internally, but the sendmail_path is the path to the sendmail program.
I didn't understand the smtp types question.
When you say from server side, are you talking about server configuration or server code?

The best way to determine which one you should use is test it sending you three emails with different protocols.

[eluser]nirbhab[/eluser]
SMTP are of two types, auth and non-auth types.

1. which require authentication
2. other one doesn't requires.

I am still little cleared, boss i need some help from you.

[eluser]Seppo[/eluser]
I was confused by [with auth and with auth] in your previous post =)

The SMTP server can be set up to require authorization or not. That is not a CI or a PHP thing, it's related to the SMTP server configuration. If you are using a shared hosting, you probably have an email where it explain how to set up the email account in a server client - There it must say if it require username & password.

[eluser]nirbhab[/eluser]
Thanks dear, i got your point, regarding smtp settings and concept.
But can you tell me whether, sendmail, uses SMTP for sending?
I know u said earlier that you don't know about the internal working about it.

but please give a try for me.

[eluser]Seppo[/eluser]
Sendmail behaves like a SMTP server, so you do not need sendmail + smtp server