]> git.immae.eu Git - github/shaarli/Shaarli.git/blame - doc/md/Server-configuration.md
doc: server configuration: remove apache logging options
[github/shaarli/Shaarli.git] / doc / md / Server-configuration.md
CommitLineData
91a21c27 1# Server configuration
992af0b9 2
992af0b9 3
992af0b9 4
91a21c27 5## Requirements
6
7### Operating system and web server
8
9Shaarli 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.
10
11You 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).
12
13Examples 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.
14
15### Network and domain name
16
17Try to host the server in a region that is geographically close to your users.
18
a32e6665 19A **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 20
6384447d 21You 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 22
41b93897 23Setup 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.
24
25Shaarli 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.
26
91a21c27 27
28### PHP
29
30Supported PHP versions:
43ad7c8e 31
bdfb967c 32Version | Status | Shaarli compatibility
33:---:|:---:|:---:
30255b79 347.3 | Supported | Yes
bdfb967c 357.2 | Supported | Yes
367.1 | Supported | Yes
899d0411 377.0 | EOL: 2018-12-03 | Yes (up to Shaarli 0.10.x)
7062ef4d 385.6 | EOL: 2018-12-31 | Yes (up to Shaarli 0.10.x)
bdfb967c 395.5 | EOL: 2016-07-10 | Yes
405.4 | EOL: 2015-09-14 | Yes (up to Shaarli 0.8.x)
415.3 | EOL: 2014-08-14 | Yes (up to Shaarli 0.8.x)
5409ade2 42
91a21c27 43Required PHP extensions:
43ad7c8e 44
bdfb967c 45Extension | Required? | Usage
46---|:---:|---
dfe14f26 47[`openssl`](http://php.net/manual/en/book.openssl.php) | requires | OpenSSL, HTTPS
3575fe5b 48[`php-json`](http://php.net/manual/en/book.json.php) | required | configuration parsing
dfe14f26 49[`php-simplexml`](https://www.php.net/manual/en/book.simplexml.php) | required | REST API (Slim framework)
bdfb967c 50[`php-mbstring`](http://php.net/manual/en/book.mbstring.php) | CentOS, Fedora, RHEL, Windows, some hosting providers | multibyte (Unicode) string support
787faa42 51[`php-gd`](http://php.net/manual/en/book.image.php) | optional | required to use thumbnails
bdfb967c 52[`php-intl`](http://php.net/manual/en/book.intl.php) | optional | localized text sorting (e.g. `e->รจ->f`)
53[`php-curl`](http://php.net/manual/en/book.curl.php) | optional | using cURL for fetching webpages and thumbnails in a more robust way
54[`php-gettext`](http://php.net/manual/en/book.gettext.php) | optional | Use the translation system in gettext mode (faster)
992af0b9 55
91a21c27 56Some [plugins](Plugins.md) may require additional configuration.
57
58
59## SSL/TLS (HTTPS)
992af0b9 60
91a21c27 61We recommend setting up [HTTPS](https://en.wikipedia.org/wiki/HTTPS) on your webserver for secure communication between clients and the server.
43ad7c8e 62
91a21c27 63For 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 64
91a21c27 65 - [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)
66 - [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)
67 - [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 68
91a21c27 69In short:
992af0b9 70
91a21c27 71```bash
72# install certbot
73sudo apt install certbot
bdfb967c 74
91a21c27 75# stop your webserver if you already have one running
76# certbot in standalone mode needs to bind to port 80 (only needed on initial generation)
77sudo systemctl stop apache2
78sudo systemctl stop nginx
bdfb967c 79
e0fe33f9 80# generate initial certificates
81# Let's Encrypt ACME servers must be able to access your server! port forwarding and firewall must be properly configured
91a21c27 82sudo certbot certonly --standalone --noninteractive --agree-tos --email "admin@shaarli.mydomain.org" -d shaarli.mydomain.org
83# this will generate a private key and certificate at /etc/letsencrypt/live/shaarli.mydomain.org/{privkey,fullchain}.pem
bdfb967c 84
91a21c27 85# restart the web server
86sudo systemctl start apache2
87sudo systemctl start nginx
88```
89
90If 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:
91
92- [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)
93- [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 94
95--------------------------------------------------------------------------------
96
91a21c27 97## Examples
98
1aeefe10 99The 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 100
101```bash
1aeefe10 102# create the document root
91a21c27 103sudo mkdir -p /var/www/shaarli.mydomain.org/
104```
105
106You can install Shaarli at the root of your virtualhost, or in a subdirectory as well. See [Directory structure](Directory-structure)
107
bdfb967c 108
91a21c27 109### Apache
bdfb967c 110
91a21c27 111```bash
112# Install apache + mod_php and PHP modules
113sudo apt update
114sudo apt install apache2 libapache2-mod-php php-json php-mbstring php-gd php-intl php-curl php-gettext
115
116# Edit the virtualhost configuration file with your favorite editor
117sudo nano /etc/apache2/sites-available/shaarli.mydomain.org.conf
118```
992af0b9 119
992af0b9 120```apache
91a21c27 121<VirtualHost *:80>
122 ServerName shaarli.mydomain.org
123 DocumentRoot /var/www/shaarli.mydomain.org/
124
91a21c27 125 # Redirect HTTP requests to HTTPS
126 RewriteEngine on
127 RewriteRule ^.well-known/acme-challenge/ - [L]
128 # except for Let's Encrypt ACME challenge requests
129 RewriteCond %{HTTP_HOST} =shaarli.mydomain.org
130 RewriteRule ^ https://shaarli.mydomain.org%{REQUEST_URI} [END,NE,R=permanent]
131</VirtualHost>
132
bdfb967c 133<VirtualHost *:443>
91a21c27 134 ServerName shaarli.mydomain.org
135 DocumentRoot /var/www/shaarli.mydomain.org/
992af0b9 136
91a21c27 137 # SSL/TLS configuration (for Let's Encrypt certificates)
bdfb967c 138 SSLEngine on
91a21c27 139 SSLCertificateFile /etc/letsencrypt/live/shaarli.mydomain.org/fullchain.pem
140 SSLCertificateKeyFile /etc/letsencrypt/live/shaarli.mydomain.org/privkey.pem
c84d1430 141
142 # Let's Encrypt settings from https://github.com/certbot/certbot/blob/master/certbot-apache/certbot_apache/_internal/tls_configs/current-options-ssl-apache.conf
143 SSLProtocol all -SSLv2 -SSLv3 -TLSv1 -TLSv1.1
144 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
145 SSLHonorCipherOrder off
146 SSLSessionTickets off
147 SSLOptions +StrictRequire
992af0b9 148
91a21c27 149 # SSL/TLS configuration (for self-signed certificates)
bdfb967c 150 #SSLEngine on
151 #SSLCertificateFile /etc/ssl/certs/ssl-cert-snakeoil.pem
152 #SSLCertificateKeyFile /etc/ssl/private/ssl-cert-snakeoil.key
992af0b9 153
bdfb967c 154 # Optional, log PHP errors, useful for debugging
155 #php_flag log_errors on
156 #php_flag display_errors on
157 #php_value error_reporting 2147483647
158 #php_value error_log /var/log/apache2/shaarli-php-error.log
992af0b9 159
91a21c27 160 <Directory /var/www/shaarli.mydomain.org/>
161 # Required for .htaccess support
992af0b9 162 AllowOverride All
992af0b9 163 Order allow,deny
bdfb967c 164 Allow from all
bdfb967c 165 </Directory>
992af0b9 166
91a21c27 167 <LocationMatch "/\.">
168 # Prevent accessing dotfiles
169 RedirectMatch 404 ".*"
170 </LocationMatch>
3cc8c898 171
91a21c27 172 <LocationMatch "\.(?:ico|css|js|gif|jpe?g|png)$">
173 # allow client-side caching of static files
174 Header set Cache-Control "max-age=2628000, public, must-revalidate, proxy-revalidate"
175 </LocationMatch>
3cc8c898 176
91a21c27 177 # serve the Shaarli favicon from its custom location
178 Alias favicon.ico /var/www/shaarli.mydomain.org/images/favicon.ico
992af0b9 179
91a21c27 180</VirtualHost>
181```
43ad7c8e 182
91a21c27 183```bash
184# Enable the virtualhost
185sudo a2ensite shaarli
992af0b9 186
91a21c27 187# mod_ssl must be enabled to use TLS/SSL certificates
188# https://httpd.apache.org/docs/current/mod/mod_ssl.html
189sudo a2enmod ssl
992af0b9 190
91a21c27 191# mod_rewrite must be enabled to use the REST API
192# https://httpd.apache.org/docs/current/mod/mod_rewrite.html
193sudo a2enmod rewrite
43ad7c8e 194
91a21c27 195# mod_version must only be enabled if you use Apache 2.2 or lower
196# https://httpd.apache.org/docs/current/mod/mod_version.html
197# sudo a2enmod version
992af0b9 198
91a21c27 199# restart the apache service
200systemctl restart apache
201```
43ad7c8e 202
91a21c27 203See [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 204
91a21c27 205### Nginx
43ad7c8e 206
538fb324 207This 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 208
992af0b9 209
91a21c27 210```bash
211# install nginx and php-fpm
212sudo apt update
213sudo apt install nginx php-fpm
992af0b9 214
91a21c27 215# Edit the virtualhost configuration file with your favorite editor
216sudo nano /etc/nginx/sites-available/shaarli.mydomain.org
992af0b9
V
217```
218
219```nginx
91a21c27 220server {
221 listen 80;
222 server_name shaarli.mydomain.org;
992af0b9 223
91a21c27 224 # redirect all plain HTTP requests to HTTPS
225 return 301 https://shaarli.mydomain.org$request_uri;
992af0b9 226}
992af0b9 227
91a21c27 228server {
229 listen 443 ssl;
230 server_name shaarli.mydomain.org;
231 root /var/www/shaarli.mydomain.org;
3cc8c898 232
91a21c27 233 # log file locations
234 # combined log format prepends the virtualhost/domain name to log entries
235 access_log /var/log/nginx/access.log combined;
236 error_log /var/log/nginx/error.log;
3cc8c898 237
91a21c27 238 # paths to private key and certificates for SSL/TLS
239 ssl_certificate /etc/ssl/shaarli.mydomain.org.crt;
240 ssl_certificate_key /etc/ssl/private/shaarli.mydomain.org.key;
992af0b9 241
778add2c 242 # Let's Encrypt SSL settings from https://github.com/certbot/certbot/blob/master/certbot-nginx/certbot_nginx/_internal/tls_configs/options-ssl-nginx.conf
243 ssl_session_cache shared:le_nginx_SSL:10m;
244 ssl_session_timeout 1440m;
245 ssl_session_tickets off;
246 ssl_protocols TLSv1.2 TLSv1.3;
247 ssl_prefer_server_ciphers off;
248 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";
249
91a21c27 250 # increase the maximum file upload size if needed: by default nginx limits file upload to 1MB (413 Entity Too Large error)
251 client_max_body_size 100m;
992af0b9 252
91a21c27 253 # relative path to shaarli from the root of the webserver
254 location / {
255 # default index file when no file URI is requested
256 index index.php;
257 try_files $uri /index.php$is_args$args;
992af0b9 258 }
992af0b9 259
91a21c27 260 location ~ (index)\.php$ {
261 try_files $uri =404;
262 # slim API - split URL path into (script_filename, path_info)
263 fastcgi_split_path_info ^(.+\.php)(/.+)$;
264 # pass PHP requests to PHP-FPM
265 fastcgi_pass unix:/var/run/php-fpm/php-fpm.sock;
266 fastcgi_index index.php;
267 include fastcgi.conf;
268 }
43ad7c8e 269
91a21c27 270 location ~ \.php$ {
271 # deny access to all other PHP scripts
272 # disable this if you host other PHP applications on the same virtualhost
273 deny all;
274 }
992af0b9 275
91a21c27 276 location ~ /\. {
277 # deny access to dotfiles
278 deny all;
279 }
992af0b9 280
91a21c27 281 location ~ ~$ {
282 # deny access to temp editor files, e.g. "script.php~"
283 deny all;
284 }
992af0b9 285
91a21c27 286 location = /favicon.ico {
287 # serve the Shaarli favicon from its custom location
288 alias /var/www/shaarli/images/favicon.ico;
289 }
992af0b9 290
91a21c27 291 # allow client-side caching of static files
292 location ~* \.(?:ico|css|js|gif|jpe?g|png)$ {
293 expires max;
294 add_header Cache-Control "public, must-revalidate, proxy-revalidate";
295 # HTTP 1.0 compatibility
296 add_header Pragma public;
297 }
f8b936e7 298
f8b936e7 299}
992af0b9
V
300```
301
91a21c27 302```bash
303# enable the configuration/virtualhost
304sudo ln -s /etc/nginx/sites-available/shaarli.mydomain.org /etc/nginx/sites-enabled/shaarli.mydomain.org
305# reload nginx configuration
306sudo systemctl reload nginx
992af0b9
V
307```
308
538fb324 309See [How to install the Nginx web server](https://www.digitalocean.com/community/tutorials/how-to-install-nginx-on-debian-10) for a complete guide.
310
992af0b9 311
91a21c27 312## Reverse proxies
992af0b9 313
91a21c27 314If 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 315
992af0b9 316
3cc8c898 317
91a21c27 318## Allow import of large browser bookmarks export
992af0b9 319
91a21c27 320Web 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 321
91a21c27 322- Apache: `/etc/php/<PHP_VERSION>/apache2/php.ini`
323- Nginx + PHP-FPM: `/etc/php/<PHP_VERSION>/fpm/php.ini` (in addition to `client_max_body_size` in the [Nginx configuration](#nginx))
992af0b9 324
91a21c27 325```ini
53ed6d7d 326[...]
91a21c27 327# (optional) increase the maximum file upload size:
328post_max_size = 100M
329[...]
330# (optional) increase the maximum file upload size:
331upload_max_filesize = 100M
332```
992af0b9 333
91a21c27 334To verify PHP settings currently set on the server, create a `phpinfo.php` in your webserver's document root
992af0b9 335
91a21c27 336```bash
337# example
338echo '<?php phpinfo(); ?>' | sudo tee /var/www/shaarli.mydomain.org/phpinfo.php
339#give read-only access to this file to the webserver user
340sudo chown www-data:root /var/www/shaarli.mydomain.org/phpinfo.php
341sudo chmod 0400 /var/www/shaarli.mydomain.org/phpinfo.php
342```
992af0b9 343
91a21c27 344Access 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 345
91a21c27 346It is recommended to remove the `phpinfo.php` when no longer needed as it publicly discloses details about your webserver configuration.
992af0b9 347
b230bf20 348
91a21c27 349## Robots and crawlers
992af0b9 350
91a21c27 351To opt-out of indexing your Shaarli instance by search engines, create a `robots.txt` file at the root of your virtualhost:
3cc8c898 352
91a21c27 353```
354User-agent: *
355Disallow: /
992af0b9 356```
bdfb967c 357
91a21c27 358By 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 359
91a21c27 360- [Robots exclusion standard](https://en.wikipedia.org/wiki/Robots_exclusion_standard)
361- [Introduction to robots.txt](https://support.google.com/webmasters/answer/6062608?hl=en)
362- [Robots meta tag, data-nosnippet, and X-Robots-Tag specifications](https://developers.google.com/search/reference/robots_meta_tag)
363- [About robots.txt](http://www.robotstxt.org)
364- [About the robots META tag](https://www.robotstxt.org/meta.html)
bdfb967c 365
b49a04f7 366
91a21c27 367## Fail2ban
bdfb967c 368
91a21c27 369[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 370
91a21c27 371```ini
372# /etc/fail2ban/filter.d/shaarli-auth.conf
373[INCLUDES]
374before = common.conf
375[Definition]
376failregex = \s-\s<HOST>\s-\sLogin failed for user.*$
377ignoreregex =
378```
bdfb967c 379
91a21c27 380```ini
381# /etc/fail2ban/jail.local
382[shaarli-auth]
383enabled = true
384port = https,http
385filter = shaarli-auth
386logpath = /var/www/shaarli.mydomain.org/data/log.txt
387# allow 3 login attempts per IP address
388# (over a period specified by findtime = in /etc/fail2ban/jail.conf)
389maxretry = 3
390# permanently ban the IP address after reaching the limit
391bantime = -1
392```
bdfb967c 393
91a21c27 394#### References
bdfb967c 395
91a21c27 396- [Apache/PHP - error log per VirtualHost - StackOverflow](http://stackoverflow.com/q/176)
bdfb967c 397- [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 398- [Server-side TLS (Apache) - Mozilla](https://wiki.mozilla.org/Security/Server_Side_TLS#Apache)
bdfb967c 399- [Nginx Beginner's guide](http://nginx.org/en/docs/beginners_guide.html)
400- [Nginx ngx_http_fastcgi_module](http://nginx.org/en/docs/http/ngx_http_fastcgi_module.html)
401- [Nginx Pitfalls](http://wiki.nginx.org/Pitfalls)
91a21c27 402- [Nginx PHP configuration examples - Karl Blessing](http://kbeezie.com/nginx-configuration-examples/)
403- [Apache 2.4 documentation](https://httpd.apache.org/docs/2.4/)
404- [Apache mod_proxy](https://httpd.apache.org/docs/2.4/mod/mod_proxy.html)
405- [Apache Reverse Proxy Request Headers](https://httpd.apache.org/docs/2.4/mod/mod_proxy.html#x-headers)
406- [HAProxy documentation](https://cbonte.github.io/haproxy-dconv/)
407- [Nginx documentation](https://nginx.org/en/docs/)
408- [`X-Forwarded-Proto`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Proto)
409- [`X-Forwarded-Host`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-Host)
410- [`X-Forwarded-For`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For)
411- [Server-side TLS (Nginx) - Mozilla](https://wiki.mozilla.org/Security/Server_Side_TLS#Nginx)
bdfb967c 412- [How to Create Self-Signed SSL Certificates with OpenSSL](http://www.xenocafe.com/tutorials/linux/centos/openssl/self_signed_certificates/index.php)
413- [How do I create my own Certificate Authority?](https://workaround.org/certificate-authority)
bdfb967c 414- [Travis configuration](https://github.com/shaarli/Shaarli/blob/master/.travis.yml)
415- [PHP: Supported versions](http://php.net/supported-versions.php)
91a21c27 416- [PHP: Unsupported versions (EOL/End-of-life)](http://php.net/eol.php)
bdfb967c 417- [PHP 7 Changelog](http://php.net/ChangeLog-7.php)
418- [PHP 5 Changelog](http://php.net/ChangeLog-5.php)
419- [PHP: Bugs](https://bugs.php.net/)
91a21c27 420- [Transport Layer Security](https://en.wikipedia.org/wiki/Transport_Layer_Security)
421- 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.
422
423