Web-Basics
A webserver delivers data over the HTTP protocoll to a web browser. Typically these are HTML, CSS, JavaScript and image files.
Dependent on the chosen webserver you can use scripting languages or deliver dynamic data with for example:
Typical webserver implementations:
Currently the distribution of webservers (22nd february 2020) is:
The Apache HTTP server ist a free to use, open source webserver which has been published in 1995 and is currently the most used webserver (February 2020 – see “What is a webserver?“).
The installations process for the Apache webserver is mostly different on every linux distribution. In the following example I will show you how to install it on a Debian/Ubuntu based system.
sudo apt-get install apache2After that you should be able to check the Apache2 version with:
apache2 -vAs usual in Debian based distributions the config files are located in /etc/apache2
In this folder we have the following files and folders:
Folder: /etc/apache2/sites-available/<filename>
<VirtualHost *:80>
ServerName www.domain.com
ServerAlias domain.com
DocumentRoot /var/www/html/docroot
</VirtualHost>ln -s /etc/apache2/sites-available/<Dateiname> /etc/apache2/sites-enabled/<Dateiname>apache2ctl configtestapache2ctl restartIn Ubuntu/Debian based systems its pretty easy since its just a package which you can install via apt-get.
sudo apt-get install -y php7.2-curl php7.2-gd php7.2-json php7.2-mbstring php7.2-mcrypt libapache2-mod-php7.2The most important package here is “libapache2-mod-php7.2” which connects the globally installed PHP and the Apache webserver. See mod_php for more details.
Instead of php7.2 you can of course use php7.3 or any other future PHP version.
If everything went well you can restart the webserver with apachectl restart and create a new file /var/www/html/info.php with the following content:
<?php phpinfo();After that you can open your webbrowser and open the following URL
http://<Server-IP>/info.php
Now you should see a PHP-Info page.
NGINX is a free to use, open source webserver which has been invented in 1999 by Igor Sysoev and ist currently the number 2 of the most used webservers (February 2020 – see „What is a webserver?„).
NGINX was created primarily because of the “C10k Problem”.
The “C10k Problem” is about optimizing and handling a large amount of network sockets.
C => Connection | 10k => 10.000
NGINX with its event based, async architecture was the base for future “high performance” server software and was therefore declared the fastest available webserver.
As mentioned in the apache installation process this can be different on your used linux distribution but the following example is based on a Debian/Ubuntu distribution.
sudo apt-get install nginxAfter that you can check the installed version with the following command:
nginx -vSimilar to other linux packages the configuration files for NGINX are located in /etc/nginx.
Here we can find the following files and folders:
Not so important files
In /etc/nginx/sites-available there is a “default” file
This basically contains the following (comments (#) have been removed)
server {
listen 80 default_server; # IPv4 listen on Port 80
listen [::]:80 default_server; # IPv6 listen on Port 80
root /var/www/html; # Absolute path to Document-Root
# Set default files to show when accessing the website
# Add index.php to the list if you are using PHP
index index.html index.htm index.nginx-debian.html;
server_name mydomain.at; # the domain name
location / {
# First attempt to serve request as file, then
# as directory, then fall back to displaying a 404.
try_files $uri $uri/ =404;
}
# pass PHP scripts to FastCGI server
#
#location ~ \.php$ {
# include snippets/fastcgi-php.conf;
#
# # With php-fpm (or other unix sockets):
# fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
# # With php-cgi (or other tcp sockets):
# fastcgi_pass 127.0.0.1:9000;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}If you want to activate your configuration you have to create a “Symlink” in the folder /etc/nginx/sites-enabled.
sudo ln -s /etc/nginx/sites-available/default /etc/nginx/sites-enabled/defaultOr if you want to deactivate an already activated config:
unlink /etc/nginx/sites-enabled/defaultBefore you restart the NGINX server you should check your config syntax if you got any typos or wrong syntax:
nginx -tAfter each change in the NGINX config you have to realod the NGINX to see the effect of the config chage
systemctl reload nginxValid HTTPS certificates are necessary to show the lock beside of your URL.
A “Certificate Authority” (short CA) is necessary to check certificates with specific, predefined methods and if that validation has been successful to sign these certificates. Additionally on each validation the certificate a date will be set when the certificate is being expired. After that period the certificate has to be checked and signed again.
In the past it was only possible to buy HTTPS certificates. But since 2015 “LetsEncrypt” or better the python script “Certbot” which makes this process way easier.
LetsEncrypt uses the “Domain-Vaildation” (DV) process. Therefore everyone, who is the owner a domain and shows the domain to a server, a signed LetsEncrypt certificate can be generated for this server to use this domain.
Certbot ist a software, which automatically generated and manages HTTPS certificates.
Currently there are even plugins available for the 2 mostly used webservers (Apache and NGINX), which even handle the configuration for the vhost files to include the certificate.
The easiest way to use certbot is to go to https://certbot.eff.org, enter your OS and your uses webserver and follow the instructions.
Usually a certificate generated by Certbot/LetsEncrypt is valid for 90 days. But Certbot checks the status of each installed certificate regularly and automatically renews certificates which will get expired in 30 days.
Therefore you only need to create and install your certificates once and everything else is handled by certbot.
