apt-get install msmtp ca-certificates

vim /etc/msmtprc
	# Set defaults.
	defaults

	# Enable or disable TLS/SSL encryption.
	tls on
	tls_starttls on
	tls_trust_file /etc/ssl/certs/ca-certificates.crt

	# Set up a default account's settings.
	account default
	host smtp.sendgrid.net
	port 587
	auth on
	user <username>
	password <password>
	from bounces@your-doman-here
	logfile /var/log/msmtp/msmtp.log

vim /etc/php5/apache2/php.ini

	sendmail_path = /usr/bin/msmtp -t

mkdir /var/log/msmtp
chown www-data:adm /var/log/msmtp
vim /etc/logrotate.d/msmtp
	/var/log/msmtp/*.log {
		rotate 12
		monthly
		compress
		missingok
		notifempty
	}