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91a21c27 1# Server configuration
992af0b9 2
91a21c27 3## Requirements
4
5### Operating system and web server
6
7Shaarli can be hosted on dedicated/virtual servers, or shared hosting. The smallest DigitalOcean VPS (Droplet with 1 CPU, 1 GiB RAM and 25 GiB SSD) costs about $5/month and will run any Shaarli installation without problems.
8
9You need write access to the Shaarli installation directory - you should have received instructions from your hosting provider on how to connect to the server using SSH (or FTP for shared hosts).
10
11Examples in this documentation are given for [Debian](https://www.debian.org/), a GNU/Linux distribution widely used in server environments. Please adapt them to your specific Linux distribution.
12
13### Network and domain name
14
15Try to host the server in a region that is geographically close to your users.
16
a32e6665 17A **domain name** ([DNS record](https://opensource.com/article/17/4/introduction-domain-name-system-dns)) pointing to the server's public IP address is required to obtain a SSL/TLS certificate and setup HTTPS to secure client traffic to your Shaarli instance.
91a21c27 18
6384447d 19You can obtain a domain name from a [registrar](https://en.wikipedia.org/wiki/Domain_name_registrar) ([1](https://www.ovh.co.uk/domains), [2](https://www.gandi.net/en/domain)), or from free subdomain providers ([1](https://freedns.afraid.org/)). If you don't have a domain name, please set up a private domain name ([FQDN](ttps://en.wikipedia.org/wiki/Fully_qualified_domain_name)) in your clients' [hosts files](https://en.wikipedia.org/wiki/Hosts_(file)) to access the server (direct access by IP address can result in unexpected behavior).
91a21c27 20
41b93897 21Setup a **firewall** (using `iptables`, [ufw](https://www.digitalocean.com/community/tutorials/how-to-set-up-a-firewall-with-ufw-on-debian-10), [fireHOL](https://firehol.org/) or any frontend of your choice) to deny all incoming traffic except `tcp/80` and `tcp/443`, which are needed to access the web server (and any other posrts you might need, like SSH). If the server is in a private network behind a NAT, ensure these **ports are forwarded** to the server.
22
23Shaarli makes outbound HTTP/HTTPS connections to websites you bookmark to fetch page information (title, thumbnails), the server must then have access to the Internet as well, and a working DNS resolver.
24
9417f133 25
26### Screencast
27
28Here is a screencast of the installation procedure
29
30[![asciicast](https://asciinema.org/a/z3RXxcJIRgWk0jM2ws6EnUFgO.svg)](https://asciinema.org/a/z3RXxcJIRgWk0jM2ws6EnUFgO)
31
02117f7e 32--------------------------------------------------------------------------------
91a21c27 33
34### PHP
35
36Supported PHP versions:
43ad7c8e 37
bdfb967c 38Version | Status | Shaarli compatibility
39:---:|:---:|:---:
30255b79 407.3 | Supported | Yes
bdfb967c 417.2 | Supported | Yes
427.1 | Supported | Yes
899d0411 437.0 | EOL: 2018-12-03 | Yes (up to Shaarli 0.10.x)
7062ef4d 445.6 | EOL: 2018-12-31 | Yes (up to Shaarli 0.10.x)
bdfb967c 455.5 | EOL: 2016-07-10 | Yes
465.4 | EOL: 2015-09-14 | Yes (up to Shaarli 0.8.x)
475.3 | EOL: 2014-08-14 | Yes (up to Shaarli 0.8.x)
5409ade2 48
91a21c27 49Required PHP extensions:
43ad7c8e 50
bdfb967c 51Extension | Required? | Usage
52---|:---:|---
dfe14f26 53[`openssl`](http://php.net/manual/en/book.openssl.php) | requires | OpenSSL, HTTPS
3575fe5b 54[`php-json`](http://php.net/manual/en/book.json.php) | required | configuration parsing
dfe14f26 55[`php-simplexml`](https://www.php.net/manual/en/book.simplexml.php) | required | REST API (Slim framework)
bdfb967c 56[`php-mbstring`](http://php.net/manual/en/book.mbstring.php) | CentOS, Fedora, RHEL, Windows, some hosting providers | multibyte (Unicode) string support
787faa42 57[`php-gd`](http://php.net/manual/en/book.image.php) | optional | required to use thumbnails
bdfb967c 58[`php-intl`](http://php.net/manual/en/book.intl.php) | optional | localized text sorting (e.g. `e->รจ->f`)
59[`php-curl`](http://php.net/manual/en/book.curl.php) | optional | using cURL for fetching webpages and thumbnails in a more robust way
60[`php-gettext`](http://php.net/manual/en/book.gettext.php) | optional | Use the translation system in gettext mode (faster)
992af0b9 61
91a21c27 62Some [plugins](Plugins.md) may require additional configuration.
63
64
65## SSL/TLS (HTTPS)
992af0b9 66
91a21c27 67We recommend setting up [HTTPS](https://en.wikipedia.org/wiki/HTTPS) on your webserver for secure communication between clients and the server.
43ad7c8e 68
38d66e1a 69### Let's Encrypt
70
91a21c27 71For public-facing web servers this can be done using free SSL/TLS certificates from [Let's Encrypt](https://en.wikipedia.org/wiki/Let's_Encrypt), a non-profit certificate authority provididing free certificates.
992af0b9 72
91a21c27 73 - [How to secure Apache with Let's Encrypt](https://www.digitalocean.com/community/tutorials/how-to-secure-apache-with-let-s-encrypt-on-debian-10)
74 - [How to secure Nginx with Let's Encrypt](https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-debian-10)
75 - [How To Use Certbot Standalone Mode to Retrieve Let's Encrypt SSL Certificates](https://www.digitalocean.com/community/tutorials/how-to-use-certbot-standalone-mode-to-retrieve-let-s-encrypt-ssl-certificates-on-debian-10).
992af0b9 76
91a21c27 77In short:
992af0b9 78
91a21c27 79```bash
80# install certbot
81sudo apt install certbot
bdfb967c 82
91a21c27 83# stop your webserver if you already have one running
84# certbot in standalone mode needs to bind to port 80 (only needed on initial generation)
85sudo systemctl stop apache2
86sudo systemctl stop nginx
bdfb967c 87
e0fe33f9 88# generate initial certificates
89# Let's Encrypt ACME servers must be able to access your server! port forwarding and firewall must be properly configured
91a21c27 90sudo certbot certonly --standalone --noninteractive --agree-tos --email "admin@shaarli.mydomain.org" -d shaarli.mydomain.org
91# this will generate a private key and certificate at /etc/letsencrypt/live/shaarli.mydomain.org/{privkey,fullchain}.pem
bdfb967c 92
91a21c27 93# restart the web server
94sudo systemctl start apache2
95sudo systemctl start nginx
96```
97
38d66e1a 98On apache `2.4.43+`, you can also delegate LE certificate management to [mod_md](https://httpd.apache.org/docs/2.4/mod/mod_md.html) [[1](https://www.cyberciti.biz/faq/how-to-secure-apache-with-mod_md-lets-encrypt-on-ubuntu-20-04-lts/)] in which case you don't need certbot and manual SSL configuration in virtualhosts.
99
100### Self-signed
101
91a21c27 102If you don't want to rely on a certificate authority, or the server can only be accessed from your own network, you can also generate self-signed certificates. Not that this will generate security warnings in web browsers/clients trying to access Shaarli:
103
104- [How To Create a Self-Signed SSL Certificate for Apache](https://www.digitalocean.com/community/tutorials/how-to-create-a-self-signed-ssl-certificate-for-apache-on-debian-10)
105- [How To Create a Self-Signed SSL Certificate for Nginx](https://www.digitalocean.com/community/tutorials/how-to-create-a-self-signed-ssl-certificate-for-nginx-on-debian-10)
bdfb967c 106
107--------------------------------------------------------------------------------
108
91a21c27 109## Examples
110
1aeefe10 111The following examples assume a Debian-based operating system is installed. On other distributions you may have to adapt details such as package installation procedures, configuration file locations, and webserver username/group (`www-data` or `httpd` are common values). In these examples we assume the document root for your web server/virtualhost is at `/var/www/shaarli.mydomain.org/`:
91a21c27 112
113```bash
d8847936 114# create the document root (replace with your own domain name)
91a21c27 115sudo mkdir -p /var/www/shaarli.mydomain.org/
116```
117
118You can install Shaarli at the root of your virtualhost, or in a subdirectory as well. See [Directory structure](Directory-structure)
119
bdfb967c 120
91a21c27 121### Apache
bdfb967c 122
91a21c27 123```bash
124# Install apache + mod_php and PHP modules
125sudo apt update
126sudo apt install apache2 libapache2-mod-php php-json php-mbstring php-gd php-intl php-curl php-gettext
127
d8847936 128# Edit the virtualhost configuration file with your favorite editor (replace the example domain name)
91a21c27 129sudo nano /etc/apache2/sites-available/shaarli.mydomain.org.conf
130```
992af0b9 131
992af0b9 132```apache
91a21c27 133<VirtualHost *:80>
134 ServerName shaarli.mydomain.org
135 DocumentRoot /var/www/shaarli.mydomain.org/
136
f3ab2616 137 # Redirect HTTP requests to HTTPS, except Let's Encrypt ACME challenge requests
91a21c27 138 RewriteEngine on
139 RewriteRule ^.well-known/acme-challenge/ - [L]
91a21c27 140 RewriteCond %{HTTP_HOST} =shaarli.mydomain.org
141 RewriteRule ^ https://shaarli.mydomain.org%{REQUEST_URI} [END,NE,R=permanent]
f3ab2616 142 # If you are using mod_md, use this instead
143 #MDCertificateAgreement accepted
144 #MDContactEmail admin@shaarli.mydomain.org
145 #MDPrivateKeys RSA 4096
91a21c27 146</VirtualHost>
147
bdfb967c 148<VirtualHost *:443>
91a21c27 149 ServerName shaarli.mydomain.org
150 DocumentRoot /var/www/shaarli.mydomain.org/
992af0b9 151
f3ab2616 152 # SSL/TLS configuration for Let's Encrypt certificates acquired with certbot standalone
bdfb967c 153 SSLEngine on
91a21c27 154 SSLCertificateFile /etc/letsencrypt/live/shaarli.mydomain.org/fullchain.pem
155 SSLCertificateKeyFile /etc/letsencrypt/live/shaarli.mydomain.org/privkey.pem
c84d1430 156 # Let's Encrypt settings from https://github.com/certbot/certbot/blob/master/certbot-apache/certbot_apache/_internal/tls_configs/current-options-ssl-apache.conf
157 SSLProtocol all -SSLv2 -SSLv3 -TLSv1 -TLSv1.1
158 SSLCipherSuite ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
159 SSLHonorCipherOrder off
160 SSLSessionTickets off
161 SSLOptions +StrictRequire
992af0b9 162
f3ab2616 163 # SSL/TLS configuration for Let's Encrypt certificates acquired with mod_md
164 #MDomain shaarli.mydomain.org
165
91a21c27 166 # SSL/TLS configuration (for self-signed certificates)
bdfb967c 167 #SSLEngine on
168 #SSLCertificateFile /etc/ssl/certs/ssl-cert-snakeoil.pem
169 #SSLCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key
992af0b9 170
bdfb967c 171 # Optional, log PHP errors, useful for debugging
172 #php_flag log_errors on
173 #php_flag display_errors on
174 #php_value error_reporting 2147483647
175 #php_value error_log /var/log/apache2/shaarli-php-error.log
992af0b9 176
91a21c27 177 <Directory /var/www/shaarli.mydomain.org/>
178 # Required for .htaccess support
992af0b9 179 AllowOverride All
ecdae223 180 Require all granted
bdfb967c 181 </Directory>
992af0b9 182
91a21c27 183 <LocationMatch "/\.">
184 # Prevent accessing dotfiles
185 RedirectMatch 404 ".*"
186 </LocationMatch>
3cc8c898 187
91a21c27 188 <LocationMatch "\.(?:ico|css|js|gif|jpe?g|png)$">
189 # allow client-side caching of static files
190 Header set Cache-Control "max-age=2628000, public, must-revalidate, proxy-revalidate"
191 </LocationMatch>
3cc8c898 192
91a21c27 193 # serve the Shaarli favicon from its custom location
194 Alias favicon.ico /var/www/shaarli.mydomain.org/images/favicon.ico
992af0b9 195
91a21c27 196</VirtualHost>
197```
43ad7c8e 198
91a21c27 199```bash
200# Enable the virtualhost
5eece37b 201sudo a2ensite shaarli.mydomain.org
992af0b9 202
91a21c27 203# mod_ssl must be enabled to use TLS/SSL certificates
204# https://httpd.apache.org/docs/current/mod/mod_ssl.html
205sudo a2enmod ssl
992af0b9 206
91a21c27 207# mod_rewrite must be enabled to use the REST API
208# https://httpd.apache.org/docs/current/mod/mod_rewrite.html
209sudo a2enmod rewrite
43ad7c8e 210
19489e92 211# mod_headers must be enabled to set custom headers from the server config
212sudo a2enmod headers
213
91a21c27 214# mod_version must only be enabled if you use Apache 2.2 or lower
215# https://httpd.apache.org/docs/current/mod/mod_version.html
216# sudo a2enmod version
992af0b9 217
91a21c27 218# restart the apache service
083b2802 219sudo systemctl restart apache2
91a21c27 220```
43ad7c8e 221
91a21c27 222See [How to install the Apache web server](https://www.digitalocean.com/community/tutorials/how-to-install-the-apache-web-server-on-debian-10) for a complete guide.
992af0b9 223
78f319fa 224
91a21c27 225### Nginx
43ad7c8e 226
538fb324 227This examples uses nginx and the [PHP-FPM](https://www.digitalocean.com/community/tutorials/how-to-install-linux-nginx-mariadb-php-lemp-stack-on-debian-10#step-3-%E2%80%94-installing-php-for-processing) PHP interpreter. Nginx and PHP-FPM must be running using the same user and group, here we assume the user/group to be `www-data:www-data`.
43ad7c8e 228
992af0b9 229
91a21c27 230```bash
231# install nginx and php-fpm
232sudo apt update
233sudo apt install nginx php-fpm
992af0b9 234
91a21c27 235# Edit the virtualhost configuration file with your favorite editor
236sudo nano /etc/nginx/sites-available/shaarli.mydomain.org
992af0b9
V
237```
238
239```nginx
91a21c27 240server {
241 listen 80;
242 server_name shaarli.mydomain.org;
992af0b9 243
91a21c27 244 # redirect all plain HTTP requests to HTTPS
245 return 301 https://shaarli.mydomain.org$request_uri;
992af0b9 246}
992af0b9 247
91a21c27 248server {
249 listen 443 ssl;
250 server_name shaarli.mydomain.org;
251 root /var/www/shaarli.mydomain.org;
3cc8c898 252
91a21c27 253 # log file locations
254 # combined log format prepends the virtualhost/domain name to log entries
255 access_log /var/log/nginx/access.log combined;
256 error_log /var/log/nginx/error.log;
3cc8c898 257
91a21c27 258 # paths to private key and certificates for SSL/TLS
259 ssl_certificate /etc/ssl/shaarli.mydomain.org.crt;
260 ssl_certificate_key /etc/ssl/private/shaarli.mydomain.org.key;
992af0b9 261
778add2c 262 # Let's Encrypt SSL settings from https://github.com/certbot/certbot/blob/master/certbot-nginx/certbot_nginx/_internal/tls_configs/options-ssl-nginx.conf
263 ssl_session_cache shared:le_nginx_SSL:10m;
264 ssl_session_timeout 1440m;
265 ssl_session_tickets off;
266 ssl_protocols TLSv1.2 TLSv1.3;
267 ssl_prefer_server_ciphers off;
268 ssl_ciphers "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384";
269
91a21c27 270 # increase the maximum file upload size if needed: by default nginx limits file upload to 1MB (413 Entity Too Large error)
271 client_max_body_size 100m;
992af0b9 272
91a21c27 273 # relative path to shaarli from the root of the webserver
274 location / {
275 # default index file when no file URI is requested
276 index index.php;
277 try_files $uri /index.php$is_args$args;
992af0b9 278 }
992af0b9 279
91a21c27 280 location ~ (index)\.php$ {
281 try_files $uri =404;
282 # slim API - split URL path into (script_filename, path_info)
283 fastcgi_split_path_info ^(.+\.php)(/.+)$;
284 # pass PHP requests to PHP-FPM
285 fastcgi_pass unix:/var/run/php-fpm/php-fpm.sock;
286 fastcgi_index index.php;
287 include fastcgi.conf;
288 }
43ad7c8e 289
91a21c27 290 location ~ \.php$ {
291 # deny access to all other PHP scripts
292 # disable this if you host other PHP applications on the same virtualhost
293 deny all;
294 }
992af0b9 295
91a21c27 296 location ~ /\. {
297 # deny access to dotfiles
298 deny all;
299 }
992af0b9 300
91a21c27 301 location ~ ~$ {
302 # deny access to temp editor files, e.g. "script.php~"
303 deny all;
304 }
992af0b9 305
91a21c27 306 location = /favicon.ico {
307 # serve the Shaarli favicon from its custom location
308 alias /var/www/shaarli/images/favicon.ico;
309 }
992af0b9 310
91a21c27 311 # allow client-side caching of static files
312 location ~* \.(?:ico|css|js|gif|jpe?g|png)$ {
313 expires max;
314 add_header Cache-Control "public, must-revalidate, proxy-revalidate";
315 # HTTP 1.0 compatibility
316 add_header Pragma public;
317 }
f8b936e7 318
f8b936e7 319}
992af0b9
V
320```
321
91a21c27 322```bash
323# enable the configuration/virtualhost
324sudo ln -s /etc/nginx/sites-available/shaarli.mydomain.org /etc/nginx/sites-enabled/shaarli.mydomain.org
325# reload nginx configuration
326sudo systemctl reload nginx
992af0b9
V
327```
328
538fb324 329See [How to install the Nginx web server](https://www.digitalocean.com/community/tutorials/how-to-install-nginx-on-debian-10) for a complete guide.
330
992af0b9 331
91a21c27 332## Reverse proxies
992af0b9 333
91a21c27 334If Shaarli is hosted on a server behind a [reverse proxy](https://en.wikipedia.org/wiki/Reverse_proxy) (i.e. there is a proxy server between clients and the web server hosting Shaarli), configure it accordingly. See [Reverse proxy](Reverse-proxy.md) configuration.
b230bf20 335
992af0b9 336
3cc8c898 337
91a21c27 338## Allow import of large browser bookmarks export
992af0b9 339
91a21c27 340Web browser bookmark exports can be large due to the presence of base64-encoded images and favicons/long subfolder names. Edit the PHP configuration file.
992af0b9 341
91a21c27 342- Apache: `/etc/php/<PHP_VERSION>/apache2/php.ini`
343- Nginx + PHP-FPM: `/etc/php/<PHP_VERSION>/fpm/php.ini` (in addition to `client_max_body_size` in the [Nginx configuration](#nginx))
992af0b9 344
91a21c27 345```ini
53ed6d7d 346[...]
91a21c27 347# (optional) increase the maximum file upload size:
348post_max_size = 100M
349[...]
350# (optional) increase the maximum file upload size:
351upload_max_filesize = 100M
352```
992af0b9 353
91a21c27 354To verify PHP settings currently set on the server, create a `phpinfo.php` in your webserver's document root
992af0b9 355
91a21c27 356```bash
357# example
358echo '<?php phpinfo(); ?>' | sudo tee /var/www/shaarli.mydomain.org/phpinfo.php
359#give read-only access to this file to the webserver user
360sudo chown www-data:root /var/www/shaarli.mydomain.org/phpinfo.php
361sudo chmod 0400 /var/www/shaarli.mydomain.org/phpinfo.php
362```
992af0b9 363
91a21c27 364Access the file from a web browser (eg. <https://shaarli.mydomain.org/phpinfo.php> and look at the _Loaded Configuration File_ and _Scan this dir for additional .ini files_ entries
992af0b9 365
91a21c27 366It is recommended to remove the `phpinfo.php` when no longer needed as it publicly discloses details about your webserver configuration.
992af0b9 367
b230bf20 368
91a21c27 369## Robots and crawlers
992af0b9 370
91a21c27 371To opt-out of indexing your Shaarli instance by search engines, create a `robots.txt` file at the root of your virtualhost:
3cc8c898 372
91a21c27 373```
374User-agent: *
375Disallow: /
992af0b9 376```
bdfb967c 377
91a21c27 378By default Shaarli already disallows indexing of your local copy of the documentation by default, using `<meta name="robots">` HTML tags. Your Shaarli instance may still be indexed by various robots on the public Internet, that do not respect this header or the robots standard.
bdfb967c 379
91a21c27 380- [Robots exclusion standard](https://en.wikipedia.org/wiki/Robots_exclusion_standard)
381- [Introduction to robots.txt](https://support.google.com/webmasters/answer/6062608?hl=en)
382- [Robots meta tag, data-nosnippet, and X-Robots-Tag specifications](https://developers.google.com/search/reference/robots_meta_tag)
383- [About robots.txt](http://www.robotstxt.org)
384- [About the robots META tag](https://www.robotstxt.org/meta.html)
bdfb967c 385
b49a04f7 386
91a21c27 387## Fail2ban
bdfb967c 388
91a21c27 389[fail2ban](http://www.fail2ban.org/wiki/index.php/Main_Page) is an intrusion prevention framework that reads server (Apache, SSH, etc.) and uses `iptables` profiles to block brute-force attempts. You need to create a filter to detect shaarli login failures in logs, and a jail configuation to configure the behavior when failed login attempts are detected:
6c44d604 390
91a21c27 391```ini
392# /etc/fail2ban/filter.d/shaarli-auth.conf
393[INCLUDES]
394before = common.conf
395[Definition]
396failregex = \s-\s<HOST>\s-\sLogin failed for user.*$
397ignoreregex =
398```
bdfb967c 399
91a21c27 400```ini
401# /etc/fail2ban/jail.local
402[shaarli-auth]
403enabled = true
404port = https,http
405filter = shaarli-auth
406logpath = /var/www/shaarli.mydomain.org/data/log.txt
407# allow 3 login attempts per IP address
408# (over a period specified by findtime = in /etc/fail2ban/jail.conf)
409maxretry = 3
410# permanently ban the IP address after reaching the limit
411bantime = -1
412```
bdfb967c 413
e21df1e7 414Then restart the service: `sudo systemctl restart fail2ban`
415
91a21c27 416#### References
bdfb967c 417
91a21c27 418- [Apache/PHP - error log per VirtualHost - StackOverflow](http://stackoverflow.com/q/176)
bdfb967c 419- [Apache - PHP: php_value vs php_admin_value and the use of php_flag explained](https://ma.ttias.be/php-php_value-vs-php_admin_value-and-the-use-of-php_flag-explained/)
91a21c27 420- [Server-side TLS (Apache) - Mozilla](https://wiki.mozilla.org/Security/Server_Side_TLS#Apache)
bdfb967c 421- [Nginx Beginner's guide](http://nginx.org/en/docs/beginners_guide.html)
422- [Nginx ngx_http_fastcgi_module](http://nginx.org/en/docs/http/ngx_http_fastcgi_module.html)
423- [Nginx Pitfalls](http://wiki.nginx.org/Pitfalls)
91a21c27 424- [Nginx PHP configuration examples - Karl Blessing](http://kbeezie.com/nginx-configuration-examples/)
425- [Apache 2.4 documentation](https://httpd.apache.org/docs/2.4/)
426- [Apache mod_proxy](https://httpd.apache.org/docs/2.4/mod/mod_proxy.html)
427- [Apache Reverse Proxy Request Headers](https://httpd.apache.org/docs/2.4/mod/mod_proxy.html#x-headers)
428- [HAProxy documentation](https://cbonte.github.io/haproxy-dconv/)
429- [Nginx documentation](https://nginx.org/en/docs/)
430- [`X-Forwarded-Proto`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto)
431- [`X-Forwarded-Host`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Host)
432- [`X-Forwarded-For`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For)
433- [Server-side TLS (Nginx) - Mozilla](https://wiki.mozilla.org/Security/Server_Side_TLS#Nginx)
bdfb967c 434- [How to Create Self-Signed SSL Certificates with OpenSSL](http://www.xenocafe.com/tutorials/linux/centos/openssl/self_signed_certificates/index.php)
435- [How do I create my own Certificate Authority?](https://workaround.org/certificate-authority)
bdfb967c 436- [Travis configuration](https://github.com/shaarli/Shaarli/blob/master/.travis.yml)
437- [PHP: Supported versions](http://php.net/supported-versions.php)
91a21c27 438- [PHP: Unsupported versions (EOL/End-of-life)](http://php.net/eol.php)
bdfb967c 439- [PHP 7 Changelog](http://php.net/ChangeLog-7.php)
440- [PHP 5 Changelog](http://php.net/ChangeLog-5.php)
441- [PHP: Bugs](https://bugs.php.net/)
91a21c27 442- [Transport Layer Security](https://en.wikipedia.org/wiki/Transport_Layer_Security)
443- Hosting providers: [DigitalOcean](https://www.digitalocean.com/) ([1](https://www.digitalocean.com/docs/droplets/overview/), [2](https://www.digitalocean.com/pricing/), [3](https://www.digitalocean.com/docs/droplets/how-to/create/), [How to Add SSH Keys to Droplets](https://www.digitalocean.com/docs/droplets/how-to/add-ssh-keys/), [4](https://www.digitalocean.com/community/tutorials/initial-server-setup-with-debian-8), [5](https://www.digitalocean.com/community/tutorials/an-introduction-to-securing-your-linux-vps)), [Gandi](https://www.gandi.net/en), [OVH](https://www.ovh.co.uk/), [RackSpace](https://www.rackspace.com/), etc.
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