申請設定 Let's Encrypt 免費 SSL 憑證(CentOS + Apache/Nginx) [Jonathan's Wiki 筆記]

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====== 申請設定 Let's Encrypt 免費 SSL 憑證(CentOS + Apache/Nginx) ======

因為 [[https://www.ithome.com.tw/news/122830|Google Chrome 自 2018/05/01]] 對於沒有合法的 SSL 網站憑證, 就會出現警告, 所以就出現要買 SSL 網站憑證的議題, 針對個人網站或是非正式的公司網站, 採用 [[https://letsencrypt.org/|Let's Encrypt 免費網站 SSL 憑證]]似乎是個不錯的選擇.

===== 申請 Let's Encrypt 與設定 Web Server 程序 =====
{{tabinclude>tech:ssl_letsencrypt:ubuntu20_04, tech:ssl_letsencrypt:alpine3_15, tech:ssl_letsencrypt:centos8, tech:ssl_letsencrypt:centos7}}

    * 這過程會檢查與安裝 python packages 並讀取 web server 的設定, 查看目前的網站網址, 如果有設定 Virtual Host 多網址, 也可以選擇產生多網域的憑證((只產生一個憑證檔案, 但該憑證檔案內有包含多個網址))
    * 原則上只要最後詢問 Please choose whether or not to redirect HTTP traffic to HTTPS, removing HTTP access. 是否要讓瀏覽 http 網址自動轉至 https 的問題後, 出現以下的訊息, 就表示已自動將 web server 的設定都改好<file>
:
Congratulations! You have successfully enabled https://www.ichiayi.com

You should test your configuration at:
https://www.ssllabs.com/ssltest/analyze.html?d=www.ichiayi.com
:
</file>
<note>
  * 如果只要產生網站憑證檔案, 可以再 certbot 後面加上 certonly 的參數 Exp.<code sh>
certbot-auto --nginx certonly
</code>
  * 這樣執行後, 會在 /etc/letsencrypt/live 目錄內, 產生該網域的憑證相關檔案目錄
</note>

===== 透過 ssllabs 來檢測是否正常 =====
  * https://www.ssllabs.com/ssltest/analyze.html?d=[網址]
  * 測試結果如下圖所示 \\ {{:tech:2018051801.png}}
  * 其中檢測 CAA Record 這一項需要在 DNS 設定, 如果想完整設定可使用以下網站協助產生設定資料 \\ https://sslmate.com/caa/ \\ 當 DNS 完成設定後, 可以使用以下網站功能檢測 \\ https://caatest.co.uk/


===== apache 相關設定 =====
  * 必須要將 /etc/httpd/conf.d/ssl.conf 內的 "SSL Virtual Host Context" 底下預設 VirtualHost 整個拿掉才能正常運作<file>
:
##
## SSL Virtual Host Context
##

#<VirtualHost _default_:443>
#:
#:
#</VirtualHost>
</file>
  * certbot-auto 會自動產生 /etc/httpd/conf/httpd-le-ssl.conf 定義 VirtualHost, 如果沒有產生要直接修改 ssl.conf ++點這裡看 wiki.ichiayi.com 範例|<file>
:
:
    # Explictly disable SSL compression (should default to off anyway...)
    # Note enabling SSL compression makes Apache vulnerable to CRIME attack.
    SSLCompression off

    # Default certificate file to use (provided by TurnKey)
    #SSLCertificateFile /etc/ssl/private/cert.pem
    SSLCertificateFile /etc/letsencrypt/live/wiki.ichiayi.com/cert.pem
    SSLCertificateKeyFile /etc/letsencrypt/live/wiki.ichiayi.com/privkey.pem

</IfModule>
</file>
<note>
  * 如果之後增加 VirtualHost 透過 <code sh>certbot-auto --apache certonly</code> 產生憑證後, 需要到 /etc/httpd/conf/httpd-le-ssl.conf 手動加上定義 
  * 如果想要讓連上 http: 自動轉 https: 則在 /etc/httpd/conf/httpd.conf 內定義, ++點這裡看範例|<file>
:
:
<VirtualHost *:80>
ServerName www.ichiayi.com
ServerAdmin admin@ichiayi.com
DocumentRoot /var/www/www.ichiayi.com_html
CustomLog logs/www.ichiayi.com-access_log common
ErrorLog logs/www.ichiayi.com-error_log
Redirect permanent / https://www.ichiayi.com/
</VirtualHost>
:
</file>++
</note>

===== nginx 相關設定 =====
  * 原則上會由 certbot-auto 自動完成修改, 但如果出現問題需要手動處理可以檢查 nginx 內的網站設定檔目錄 /etc/nginx/conf.d
  * Exp. www.ichiayi.com 的設定檔路徑 : ++/etc/nginx/conf.d/www_ichiayi.conf |<file>
server {
        server_name     www.ichiayi.com;

        access_log /var/log/nginx/www.ichiayi.com.access.log main;
        error_log /var/log/nginx/www.ichiayi.com.error.log;

        location / {
       :
       :
        }

    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/www.ichiayi.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/www.ichiayi.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}

server {
    if ($host = www.ichiayi.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


        listen  80;
        server_name     www.ichiayi.com;
    return 404; # managed by Certbot


}
</file>++


===== 設定自動更新憑證 =====
  * 因為免費憑證只有 3 個月的有效期, 所以自動檢查與更新是很重要
  * certbot 就具有自動更新的功能, 可設定每天檢查三次(00:00 08:00 16:00), 執行時先隨機取 3600 中的一個秒數等待, 避免造成同時間大家一起連上 Let's Encrypt 主機, 方式如下
    * CentOS 7<code sh>
vi /etc/crontab</code><file>
:
# let's encrypt
0 */8 * * * root python -c 'import random; import time; time.sleep(random.random() * 3600)' && certbot renew > /tmp/cert-bot_renew.log
</file><code sh>
service crond restart
</code>
  * 之後就可以在 /tmp/cert-bot_renew.log 看到檢查更新的紀錄

===== 手動申請 *.ichiayi.com 的 SSL 網域憑證方式 =====
  - 執行以下的語法 <code sh>
/root/lets-encrypt/certbot-auto -d ichiayi.com -d *.ichiayi.com --manual --preferred-challenges dns certonly --server https://acme-v02.api.letsencrypt.org/directory
</code>
  - 當出現以下第二次的 **Before continuing, verify the record is deployed.** 必須去設定 ichiayi.com 的 DNS<file>
Please deploy a DNS TXT record under the name
_acme-challenge.ichiayi.com with the following value:

0sGmQQTfit9lW3okOa4jaYmefNQS4FsF6zZgEtyppKw

Before continuing, verify the record is deployed.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Press Enter to Continue

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Please deploy a DNS TXT record under the name
_acme-challenge.ichiayi.com with the following value:

fEsd-DYrN-AB_XVWb-Aa9Yx9OxCofBlFkxNmt7RWiCk

Before continuing, verify the record is deployed.
</file>
  - 將前面兩次出現的 hash 值正確設定到 ichiayi.com 的 DNS TXT Record 內, Exp. <file>
:
;
$TTL 86400      ; 1 day -- ; 3 hours
$ORIGIN ichiayi.com.
@               IN SOA  ns1 server (
                                2018123100 ; serial
                                28800       ; refresh (2 hours)
                                14400        ; retry (15 minutes)
                                720000     ; expire (1 week)
                                86400      ; minimum (12 hours)
                                )
                        NS      ns4.everplast.net.
                        NS      ns7.ichiayi.com.
;
; lets-encrypt SSL Cert
_acme-challenge IN TXT  "0sGmQQTfit9lW3okOa4jaYmefNQS4FsF6zZgEtyppKw"
_acme-challenge IN TXT  "fEsd-DYrN-AB_XVWb-Aa9Yx9OxCofBlFkxNmt7RWiCk"
;
:
</file>
  - 重新啟動 DNS 讓這兩個 TXT 生效, 可透過 nslookup 指定詢問 server 8.8.8.8 來確認 <file>
C:\Users\jonathan>nslookup
預設伺服器:  UnKnown
Address:  192.168.1.5
> server 8.8.8.8
預設伺服器:  google-public-dns-a.google.com
Address:  8.8.8.8
> _acme-challenge.ichiayi.com
伺服器:  google-public-dns-a.google.com
Address:  8.8.8.8
名稱:    _acme-challenge.ichiayi.com
> set type=txt
> _acme-challenge.ichiayi.com
伺服器:  google-public-dns-a.google.com
Address:  8.8.8.8
未經授權的回答:
_acme-challenge.ichiayi.com  text =
        "fEsd-DYrN-AB_XVWb-Aa9Yx9OxCofBlFkxNmt7RWiCk"
_acme-challenge.ichiayi.com  text =
        "0sGmQQTfit9lW3okOa4jaYmefNQS4FsF6zZgEtyppKw"
</file> 
  - 確認可以正確查詢到這兩個新增的 TXT Record 後才可執行下一步, 當出現以下訊息就表示正確產生<file>
:
Waiting for verification...
Cleaning up challenges

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/ichiayi.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/ichiayi.com/privkey.pem
   Your cert will expire on 2019-03-31. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot-auto
   again. To non-interactively renew *all* of your certificates, run
   "certbot-auto renew"
 - Your account credentials have been saved in your Certbot
   configuration directory at /etc/letsencrypt. You should make a
   secure backup of this folder now. This configuration directory will
   also contain certificates and private keys obtained by Certbot so
   making regular backups of this folder is ideal.
 - 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
</file>

===== 相關重點檔案 =====
  * /root/lets-encrypt/certbot-auto (下載時指定位置)
  * /etc/letsencrypt/ 存放執行 certbot-auto 自動申請 SSL 相關憑證與檔案
  * /var/log/letsencrypt/ 存放執行 certbot-auto 的紀錄檔案

===== 透過 CloudFlare DNS 自動更新無 Web 對外網站 SSL 憑證 =====
  * 因為部份網站是內部網站, 並無法對外透過 Web 方式認證自動更新憑證, 所以需要透過 DNS 即時建立 TXT Record 來認證, 如要自動認證, 就需要透過 DNS 提供整合 API 才能達成
{{tabinclude>tech:ssl_letsencrypt:cf_ubuntu20_04, tech:ssl_letsencrypt:cf_centos8, tech:ssl_letsencrypt:cf_centos7, tech:ssl_letsencrypt:cf_centos6}}

===== 參考網址 =====
  * https://certbot.eff.org/lets-encrypt/centos6-apache
  * https://certbot.eff.org/lets-encrypt/centosrhel7-other
  * https://gitpress.io/@chchang/ubuntu-letsencrypt-cloudflare-wildcard
  * https://blog.anzupop.com/posts/acquire-lets-encrypt-certs-using-dns-cloudflare-plugin/
  * https://serverfault.com/questions/744960/configuring-ssl-with-virtual-hosts-under-apache-and-centos
  * https://sslmate.com/caa/
  * https://blog.heckel.xyz/2018/08/05/issuing-lets-encrypt-certificates-for-65000-internal-servers/
  * https://community.letsencrypt.org/t/how-to-manually-renew-a-certificate/11263/3
  * https://certbot.eff.org/docs/using.html#pre-and-post-validation-hooks
  * https://dafzheng.wordpress.com/2018/03/08/%E5%9C%A8nginx%E4%B8%8A%E4%BD%BF%E7%94%A8lets-encrypt%E5%B0%87%E7%B6%B2%E9%A0%81%E8%A8%AD%E6%88%90https/

{{tag>SSL 免費憑證}}