查看是否已经安装了mailx，如果已经安装会显示出版本号

mailx -V
安装mailx

yum install -y mailx
qq邮箱设置IMAP/SMTP服务，qq邮箱 > 设置 > 账户 > POP3/IMAP/SMTP/Exchange/CardDAV/CalDAV服务。只需开通IMAP/SMTP 服务即可，赋值授权码

配置mail.rc文件

vim /etc/mail.rc
# 邮箱
set from=358911***@qq.com
set smtp=smtps://smtp.qq.com:465
# 邮箱
set smtp-auth-user=358911***@qq.com
# 授权码
set smtp-auth-password=iptccbkvorzv***
set smtp-auth=login
set ssl-verify=ignore
# 证书所在目录
set nss-config-dir=/root/.certs
获取证书

mkdir -p /root/.certs/
echo -n | openssl s_client -connect smtp.qq.com:465 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > ~/.certs/qq.crt
certutil -A -n "GeoTrust SSL CA" -t "C,," -d ~/.certs -i ~/.certs/qq.crt
certutil -A -n "GeoTrust Global CA" -t "C,," -d ~/.certs -i ~/.certs/qq.crt
cd /root/.certs/
certutil -A -n "GeoTrust SSL CA - G3" -t "Pu,Pu,Pu" -d ~/.certs/./ -i qq.crt
certutil -L -d /root/.certs
发送邮件

echo "我是正文" | mail -s "我是主题" *********@q'q.com
测试了一下发送邮件还是挺快的，利用mailx就可以写个监控网站是否可以正常访问邮件通知的脚本