Let’s Encrypt 是一个自动签发 https 证书的免费项目
Certbot 是 Let’s Encrypt 官方推荐的证书生成客户端工具
基本操作
0 准备工作
将要签发证书的域名(如 you.domain.com) 解析到一台可在外网正常访问的服务器
1 登录服务器
my-pc$ ssh [email protected]
2 安装 certbot
这里以 Ubuntu 16.04 为例
各个系统的安装方式不一样，可以在官网首页查阅
my-server$ cat /etc/issue
Ubuntu 16.04.2 LTS \n \l
my-server$ sudo apt-get update
my-server$ sudo apt-get install software-properties-common
my-server$ sudo add-apt-repository ppa:certbot/certbot
my-server$ sudo apt-get update
my-server$ sudo apt-get install certbot
my-server$ certbot --version
certbot 0.19.0
3 检查端口占用
如果服务器上的 443 端口正在被占用，请先关闭对应的服务进程
否则可能个导致 certbot 运行出错
4 以命令交互方式开始制作证书
my-server$ certbot certonly --------> 开启命令
Saving debug log to /var/log/letsencrypt/letsencrypt.log
How would you like to authenticate with the ACME CA?
1: Spin up a temporary webserver (standalone)
2: Place files in webroot directory (webroot)
Select the appropriate number [1-2] then [enter]
(press 'c' to cancel): 1 --------> 这里我们选择 1 standalone 模式
Plugins selected: Authenticator standalone, Installer None
Enter email address (used for urgent renewal and security notices) (Enter 'c' to
cancel): [email protected] --------> 输入你的邮箱创建账号(只有第一次使用时会出现)
Please read the Terms of Service at
https://letsencrypt.org/documents/LE-SA-v1.1.1-August-1-2016.pdf. You must agree
in order to register with the ACME server at
https://acme-v01.api.letsencrypt.org/directory
(A)gree/(C)ancel: a --------> 选择 A 同意 (只有第一次使用时会出现)
Would you be willing to share your email address with the Electronic Frontier
Foundation, a founding partner of the Let's Encrypt project and the non-profit
organization that develops Certbot? We'd like to send you email about EFF and
our work to encrypt the web, protect its users and defend digital rights.
(Y)es/(N)o: y --------> 选择 Y 或 N (只有第一次使用时会出现)
Please enter in your domain name(s) (comma and/or space separated) (Enter 'c'
to cancel): you.domain.com --------> 这里输入要制作证书的域名
Obtaining a new certificate
Performing the following challenges:
tls-sni-01 challenge for you.domain.com
Waiting for verification...
Cleaning up challenges
IMPORTANT NOTES:
- Congratulations! Your certificate and chain have been saved at:
/etc/letsencrypt/live/you.domain.com/fullchain.pem
Your key file has been saved at:
/etc/letsencrypt/live/you.domain.com/privkey.pem
Your cert will expire on 2018-01-26. To obtain a new or tweaked
version of this certificate in the future, simply run certbot
again. To non-interactively renew *all* of your certificates, run
"certbot renew"
- If you like Certbot, please consider supporting our work by:
Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate
Donating to EFF: https://eff.org/donate-le
my-server$ ls /etc/letsencrypt/live/you.domain.com/ --------> 证书文件目录
cert.pem chain.pem fullchain.pem privkey.pem README
看到 IMPORTANT NOTES 下方出现 Congratulations 就表明证书已经成功签发
可以进入 /etc/letsencrypt/live/you.domain.com/ 目录查看相关生成的文件
进阶操作
使用 80 端口
默认 standalone 是使用 443 端口，也就是说要停止服务器现在占用 443 端口的进程
我们也可以将其改为使用 80 端口，同样道理，这时需要停止 80 端口的占用
my-server$ certbot certonly --standalone -n --agree-tos --email [email protected] --preferred-challenges http -d you.domain.com
-n 非交互式
--email 指定账户
--agree-tos 同意服务协议
使用 nginx 模式
安装 nginx 和插件
my-server$ apt-get install nginx
my-server$ apt-get install python-certbot-nginx
增加 nginx 配置
server {
server_name you.domain.com;
}
制作证书
my-server$ certbot --nginx -d you.domain.com
使用 webroot 模式
standalone 需要停止服务器，nginx 模式需要修改配置，如果需要在不影响服务器正常运行的情况下制作证书，可以选择 webroot 模式
有个前提，需要你的服务的 80 端口上运行一个能处理静态文件的 web 服务，我们就以 nginx 为例 (注意，webroot + nginx 与 nginx 是完全不同的两种方式)
先确定一个 webroot 目录，这里以 /var/www/html/ 为例
server {
listen 80 default_server;
location / {
alias /var/www/html/;
}
}
重启 nginx ，制作证书
my-server$ nginx -s reload
my-server$ certbot certonly --webroot -w /var/www/html/ -d you.domain.com
在执行命令后，certbot 会向指定的 webroot 目录中添加一个随机文件，随后 letsencrypt 会通过 http 访问那个文件，比如 http://you.domain.com/.well-known/acme-challenge/gdEMr7ZXOiZE51he9QwuvnbrrTnkwlpFhNAcArBt2uE， 如果能返回正确的数据则通过认证，否则认证失败
所以，即使不使用 nginx，只要能保证你的服务器能正确的返回 webroot 下的文件就行
使用 manual 模式
manual 模式其实和 webroot 类似，主要的区别就是 certbot 自动向 webroot 添加文件的过程，变为你自己手动完成
my-server$ certbot certonly --manual -d you.domain.com
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for you.domain.com
NOTE: The IP of this machine will be publicly logged as having requested this
certificate. If you're running certbot in manual mode on a machine that is not
your server, please ensure you're okay with that.
Are you OK with your IP being logged?
(Y)es/(N)o: y --------> 选 Y
Create a file containing just this data:
_Pamo3hOMx37O-KHIioWO1P0hbTLZusEZ2a2iCf7PDQ.8CyQk-SfDMR10nk7DuGBFA4IEpVhm1OySU-nSItD1BE
And make it available on your web server at this URL:
http://you.domain.com/.well-known/acme-challenge/_Pamo3hOMx37O-KHIioWO1P0hbTLZusEZ2a2iCf7PDQ
Press Enter to Continue
--------> 你需要保证 http://you.domain.com/.well-known/acme-challenge/_Pamo3hOMx37O-KHIioWO1P0hbTLZusEZ2a2iCf7PDQ
这个 url 返回的结果为 _Pamo3hOMx37O-KHIioWO1P0hbTLZusEZ2a2iCf7PDQ.8CyQk-SfDMR10nk7DuGBFA4IEpVhm1OySU-nSItD1BE (这个数据是随机的，每次都不一样)
当你做到后，按下回车键继续
Waiting for verification...
Cleaning up challenges
IMPORTANT NOTES:
- Congratulations! Your certificate and chain have been saved at:
/etc/letsencrypt/live/you.domain.com/fullchain.pem
Your key file has been saved at:
/etc/letsencrypt/live/you.domain.com/privkey.pem
Your cert will expire on 2018-01-27. To obtain a new or tweaked
version of this certificate in the future, simply run certbot
again. To non-interactively renew *all* of your certificates, run
"certbot renew"
- If you like Certbot, please consider supporting our work by:
Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate
Donating to EFF: https://eff.org/donate-le
查看和管理当前服务器上的所有证书
my-server$ certbot certificates
使用 https 证书
以 nginx 为例
server {
listen 80;
listen 443 ssl;
server_name you.domain.com;
ssl_certificate /etc/letsencrypt/live/you.domain.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/you.domain.com/privkey.pem;
# ...
}
letsencrypt 有什么限制
标准限制
- 同一个顶级域名下的二级域名，一周做多申请 20 个
- 一个域名一周最多申请 5 次
- 1 小时最多允许失败 5 次
- 请求频率需要小于 20 次/s
- 一个 ip 3 小时内最多创建 10 个账户
- 一个账户最多同时存在 300 个 pending 的审核
测试模式限制
在 certbot 命令后加上 --staging 参数，限制更松一些，但不是正式证书
- 同一个顶级域名下的二级域名，一周做多申请 30000 个
- 一个域名一周最多申请 30000 次
- 1 小时最多允许失败 60 次
- 一个 ip 3小时内最多创建 50 个账户
签发泛域名证书
先升级到最新版本的 certbot，然后
my-server$ certbot certonly -d *.aabbcc.com --manual --server https://acme-v02.api.letsencrypt.org/directory --preferred-challenges dns