一、服务端：

  1. 域名解析：
角色                        记录类型                        主机记录                        记录值
主域名                    A                                    @                                   104.225.233.249
邮件域名                A                                     mail                                104.225.233.249
邮件服务器             MX                                 @                                   mail.dollarphp.com
反垃圾配置             TXT                                @                                  v=spf1 a mx ~al

2. 卸载sendmail：

yum  -y  remove  sendmail
  1. 安装软件：
yum  -y  install  postfix  dovecot  cyrus-sasl-*  mailx
  1. 配置postfix： vim /etc/postfix/main.cf
queue_directory = /var/spool/postfix
command_directory = /usr/sbin
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
mail_owner = postfix
myhostname = mail.dollarphp.com 		#这里要换成你自己的邮箱服务器
mydomain = dollarphp.com 				#这里换成你自己的主机服务器
myorigin = $mydomain
inet_interfaces = all
inet_protocols = ipv4
mydestination = $myhostname, localhost.$mydomain, localhost,$mydomain,mail.$mydomain,www.$mydomain, ftp.$mydomain
local_recipient_maps =
unknown_local_recipient_reject_code = 550
mynetworks = 0.0.0.0/0
relay_domains = $mydestination
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
home_mailbox = Maildir/
smtpd_banner = $myhostname ESMTP
debug_peer_level = 2
debugger_command =
	 PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
	 ddd $daemon_directory/$process_name $process_id & sleep 5
sendmail_path = /usr/sbin/sendmail.postfix
newaliases_path = /usr/bin/newaliases.postfix
mailq_path = /usr/bin/mailq.postfix
setgid_group = postdrop
html_directory = no
manpage_directory = /usr/share/man
sample_directory = /usr/share/doc/postfix-2.10.1/samples
readme_directory = /usr/share/doc/postfix-2.10.1/README_FILES
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
broken_sasl_auth_clients = yes
smtpd_recipient_restrictions = permit_sasl_authenticated,reject_unauth_destination,permit_mynetworks
smtpd_client_restrictions = permit_sasl_authenticated
  1. 配置dovecot： a. 配置监听协议： vim /etc/dovecot/dovecot.conf
protocols = imap pop3 lmtp
listen = *
dict {
}
!include conf.d/*.conf
!include_try local.conf

b. 配置登录方式： vim /etc/dovecot/conf.d/10-auth.conf

disable_plaintext_auth = no
auth_mechanisms = plain login
!include auth-system.conf.ext

c. 配置邮件存储位置： vim /etc/dovecot/conf.d/10-mail.conf

mail_location = maildir:~/Maildir
namespace inbox {
  inbox = yes
}
first_valid_uid = 1000
mbox_write_locks = fcntl

d. 配置ssl（关闭）： vim /etc/dovecot/conf.d/10-ssl.conf

ssl = no
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
ssl_key = </etc/pki/dovecot/private/dovecot.pem
  1. 配置sasl2： a. 配置系统认证： vim /etc/sysconfig/saslauthd
SOCKETDIR=/run/saslauthd
MECH=shadow
FLAGS=

b. 配置登录方式（创建新文件）： vim /usr/lib64/sasl2/smtpd.conf

pwcheck_method: saslauthd
mech_list: PLAIN LOGIN
log_level:3
  1. 添加用户：
useradd  dollarphp
passwd  dollarphp
  1. 启动服务：
systemctl  start  dovecot
systemctl  start  postfix
systemctl  start  saslauthd
  1. 配置mailx： vim /etc/mail.rc
set hold
set append
set ask
set crt
set dot
set keep
set emptybox
set indentprefix="> "
set quote
set sendcharsets=iso-8859-1,utf-8
set showname
set showto
set newmail=nopoll
set autocollapse
set markanswered
ignore received in-reply-to message-id references
ignore mime-version content-transfer-encoding
fwdretain subject date from to
set bsdcompat
set from=adminmail@dollarphp.com
set smtp=mail.dollarphp.com
set smtp-auth-user=adminmail
set smtp-auth-password=123456
set smtp-auth=login
  1. 发送邮件：
echo  "内容"  |  mail  -s  "标题"  complet@163.com
或
mail  -s  "标题"  complet@163.com  <  test.txt
  1. 查看发送日志：
tail  /var/log/maillog

二、客户端：

  1. linux（接收）： a. 安装telnet：
yum  -y  install  telnet

b. 登录（dovecot的默认端口是110）：

telnet  104.225.233.249  110

c. 测试： d. 命令介绍：

USER  xxx：输入用户名
PASS  xxx：输入密码
LIST：显示信箱
RETR n：打开第n封信

e. 退出telnet：

ctl+]
quit
  1. windows（发送+接收）： a. 安装foxmail（官网：http://www.foxmail.com/）： b. 登录： c. 测试：