i've read some threads here in SO that someone managed to use gmail's smtp server to send out messages from php script.

so if php sends a mail to [email protected] it looks like this:

1. php tells sendmail (smtp server) to send the message
2. sendmail sends the message to gmail's smtp server
3. gmail's smtp server sends the message to hotmail's smtp server

so now i wonder, why should one use gmail's smtp server to send a mail? isn't it better just to send the message from sendmail to hotmail's smtp server?

correct me if im wrong, but isnt all that requires for a mail to be sent a communication between TWO smtp servers, the senders and the receivers (in this case, hotmail)?

and another question, why can't php just send the message directly to hotmail's smtp server, why does it have to go through a local smtp server?

and why do you call it a smtp server when sendmail is just acting like a client to send a message and does not receive anything?

would be great if someone could shed a light on this topic!