自己的騰訊云服務器上跑了點小應用，本想著沒什么內容就沒必要弄 https了，但是同學還是強烈建議我加上去。之后用http訪問沒備案服務器會提示“該網站暫時無法訪問”，https 的沒有這個影響，不禁覺得加上 https 是個明智的選擇。
## 安裝
在網上找到的大部分是從源代碼編譯開始用的，找到一個 certbot ，是用 PPA 裝的軟件，方便不少。
https://certbot.eff.org/
以我自己的配置來說（Ubuntu 16.04 + Nginx），安裝的命令是這樣的：
$ sudo apt-get update
$ sudo apt-get install software-properties-common
$ sudo add-apt-repository ppa:certbot/certbot
$ sudo apt-get update
$ sudo apt-get install python-certbot-nginx
具體命令，在上面的鏈接中正確選擇好就會顯示。
## 配置
運行 ``` sudo letsencrypt certonly ```
提示
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):
選擇1
Please enter in your domain name(s) (comma and/or space separated)? (Enter 'c' to cancel):
根據提示輸入域名
出現類似于以下內容就是正確配置了
```
IMPORTANT NOTES:
- Congratulations! Your certificate and chain have been saved at
/etc/letsencrypt/live/domain.com/fullchain.pem. Your cert will
expire on 2017-10-13. 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
生成2048位 DH parameters：
sudo openssl dhparam -out /etc/ssl/certs/dhparams.pem 2048
## 修改 Nginx 配置
在 /etc/nginx/sites-enabled 下新建文件，添加以下內容
server {
listen 443 ssl;
server_name domain.com;
ssl_certificate /etc/letsencrypt/live/domain.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/domain.com/privkey.pem;
ssl_dhparam /etc/ssl/certs/dhparams.pem;
ssl_ciphers 'ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-A? ? ES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-S? ? HA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-? ? AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-S? ? HA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC? ? 3-SHA';
ssl_prefer_server_ciphers on;
}
重啟 Nginx 后即可生效。
