php – 是否可以在没有SMTP设置的情况下发送邮件？

Note: The Windows implementation of mail() differs in many ways from
the Unix implementation. First,it doesn’t use a local binary for
composing messages but only operates on direct sockets which means a
MTA is needed listening on a network socket (which can either on the
localhost or a remote machine). Second,the custom headers like From:,
Cc:,Bcc: and Date: are not interpreted by the MTA in the first place,
but are parsed by PHP. As such,the to parameter should not be an
address in the form of “Something “. The mail
command may not parse this properly while talking with the MTA.

Note: It is worth noting that the mail() function is not suitable for larger volumes of email in a loop. This function opens and closes an SMTP socket for each email,which is not very efficient.