一、域名解析

A解析
类型: A 
名称: mail
值: 服务器IP

MX解析
类型: MX
名称: 域名 (也就是根域名 @)
值: mail.域名
优先级: 10

TXT解析
类型: TXT
名称: 域名 (根域名 @)
值: v=spf1 mx -all

TXT解析
类型: TXT
名称: _dmarc
值: v=DMARC1; p=quarantine;rua=mailto:admin@域名

二、前置环境安装

1.更新软件源、安装常用包

分开执行
sudo apt update
sudo apt install curl apt-transport-https ca-certificates software-properties-common -y

2.安装Docker

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

3.安装dockercompose

sudo curl -L "https://github.com/docker/compose/releases/latest/download/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

4.安装docker关键包并验证docker

sudo apt update

sudo apt install docker-ce docker-ce-cli containerd.io -y

sudo docker run --rm hello-world

sudo chmod +x /usr/local/bin/docker-compose

docker-compose --version

sudo systemctl status docker

三、安装Mailcow

# 安装
sudo git clone https://github.com/mailcow/mailcow-dockerized

cd mailcow-dockerized

# 下一步会提示设置hostname  就是域名，例如你是 123.com 那就填 mail.123.com然后是时区 就填 Asia/Shanghai，
然后就是选择分支，默认1即可

sudo ./generate_config.sh 

# 启动 Mailcow
sudo docker-compose pull

sudo docker-compose up -d

四、安装Caddy配置反代自动续签证书

1.安装caddy

sudo apt update
sudo apt install -y debian-keyring debian-archive-keyring apt-transport-https curl

# 添加 Caddy 官方 GPG key
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | sudo tee /etc/apt/trusted.gpg.d/caddy-stable.asc

# 添加 Caddy 官方 APT 源
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/debian.deb.txt' | sudo tee /etc/apt/sources.list.d/caddy-stable.list

# 安装
sudo apt update
sudo apt install -y caddy

2.如果遇到报错

# 1) 清理旧配置（如果不存在也没关系）
sudo rm -f /etc/apt/sources.list.d/caddy-stable.list
sudo rm -f /etc/apt/trusted.gpg.d/caddy-stable.asc

# 2) 放置新 key（dearmor 到 keyrings）
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://dl.cloudsmith.io/public/caddy/stable/gpg.key \
  | sudo gpg --dearmor -o /etc/apt/keyrings/caddy-stable-archive-keyring.gpg

# 3) 正确写入 APT 源（Ubuntu 22.04 = jammy）
echo "deb [signed-by=/etc/apt/keyrings/caddy-stable-archive-keyring.gpg] \
https://dl.cloudsmith.io/public/caddy/stable/deb/ubuntu jammy main" \
| sudo tee /etc/apt/sources.list.d/caddy-stable.list > /dev/null

echo "deb-src [signed-by=/etc/apt/keyrings/caddy-stable-archive-keyring.gpg] \
https://dl.cloudsmith.io/public/caddy/stable/deb/ubuntu jammy main" \
| sudo tee -a /etc/apt/sources.list.d/caddy-stable.list > /dev/null

# 4) 更新并安装
sudo apt update
sudo apt install -y caddy

# （可选）确认版本
caddy version

3.配置反代

vi /etc/caddy/Caddyfile

mail.example.com {
    reverse_proxy 127.0.0.1:18080
}

配置好之后Caddy会自动申请并配置HTTPS证书

4.测试与生效

检查配置是否正确：

sudo caddy validate --config /etc/caddy/Caddyfile

重新加载 Caddy：

sudo systemctl reload caddy

打开浏览器访问 https://mail.example.com， 应当看到你的后端服务。

默认管理员账号：admin

默认管理员密码：moohoo