I am working for a small Ho Chi Minh City company whose only server was just one old small computer. Now just a few months later, we are expanding rapidly and one of the req
I recommend installing Postfix MTA to send e-mails out the Ubuntu server:
aptitude install postfix
And using the PHP Mailer class to send e-mails from PHP: http://phpmailer.worxware.com/
For "fully featured" e-mail services my recipe is:
Postfix + DKIM-proxy + Dovecot + Roundcube + PHP Mailer + SpamAssassin + proper DNS settings + SSL certificate to enable encrypted connections
(And I prefer NginX as HTTP server...)