msmtp 是一款專門負責郵件傳送的客戶端軟體，基於GPL釋出，支援TLS/SSL、DNS模式、IPv6、伺服器端認證、多使用者等特性。

安裝相關庫

apt-get install msmtp
apt-get install gnutls-bin
apt-get install ca-certificates

配置

編輯~/.msmtprc

defaults
tls on
tls_starttls on
tls_trust_file /etc/ssl/certs/ca-certificates.crt

account default
host smtp.gmail.com
port 587
 

auth on
user [email protected]
password yourpassword
from [email protected]
logfile ~/.msmtp.log

建立log檔案

touch ~/.msmtp.log

測試

msmtp [email protected].com < test.file

附，如果傳送失敗那多半是證書問題，把gmail安全保護關閉，進入下面這兩個網站設定：

You need to allow less secure apps, you can do it by click
below link

https
 
://www.google.com/settings/security/lesssecureapps

also try this one

https://accounts.google.com/DisplayUnlockCaptcha

if still not works try changing password for gmail