1. Apache web server
Quick overview

2. About
An open source web server. Mostly for Unix, Linux and Solaris platforms
Apache is the most popular web server on the net.
It is very secure, fast, and reliable.
Created by Apache foundation
Apache foundation started to support the web server project, but now extends to a multitude of other projects. (tomcat, hadoop, ant etc. etc)

3. Features Modern, secure, multi-threaded server.
Multiple protocols: HTTP and HTTPS (FTP, proxy etc.)
It provides a full range of Web server features, including CGI, SSL, and virtual hosts.
Modular design:
most features implemented thorough loadable modules, Including (but not exhaustive):
dynamic content via interpreting languages (PHP)
authentication via lots of different back-ends (database, LDAP, pam etc.)
database support
proxying etc.
Full list:
To put it another way: if Apache can't do it, it's not wort doing.

4. Features II Virtual hosting is one of the most important features
Virtual hosting is a method for hosting multiple domain names (with separate handling of each name) on a single server (or pool of servers). This allows one server to share its resources, such as memory and processor cycles, without requiring all services provided to use the same host name.
Apache Provides multiple options of virtual hosting and scales
Name Based virtual hosts
IP Based Virtual Hosts
Aliases
Its recommended to use an IP address over hostnames in virtual hosting configuration

5. IP vs. Name?
In the „good old days“ HTTP ruled, name based virtual hosting was common
One could not do HTTPS name based virtual hosting, because TLS handshake must be completed BEFORE http request.
Problem IP adresses are more and more scarse
Solution: SNI
Server Name Indication (SNI) is an extension to the TLS computer networking protocol by which a client indicates which hostname it is attempting to connect to at the start of the handshaking process. This allows a server to present multiple certificates on the same IP address and TCP port number and hence allows multiple secure (HTTPS) websites (or any other Service over TLS) to be served off the same IP address without requiring all those sites to use the same certificate. It is the conceptual equivalent to HTTP/1.1 name-based virtual hosting, but for HTTPS. The desired hostname is not encrypted, so an eavesdropper can see which site is being requested.

6. Apache and TLS Lets review some key points Default TLS port is 443
HTTPS is important to protect communication between browser and web-server
Implenetation requires the creation of SSL certificates and Certificate Signing Requests (CSR)
For integrity SSL certificates are signed by a Certificate Authority’s (CA) such as Verisign
Self signed Certificates will also work but your browser will not trust it and will give a warning to users (which most don’t read)
To use a HTTPS feature a module must be loaded first

7. SSL Certificate Each SSL certificate has a Public and Private key
The Public Key is used to encrypt the information
The Public Key is accessible to everyone
The private Key is used to decipher the information
The private should be not be disclosed

8. Role of CA There are a number of CA that certify certificates
Most browsers have pre-included public Keys from the CA’s
A CA certified certificate will have validation information signed by the CA’s private key
The browser will decrypt the validation information using the public key and verify that the certificate is certified by the CA
If this fails a warning is given
Security tip: it's actually very easy and cheap to obtain an „simple“ certificate. Only domain ownership validation are done.
most users do not notice nor understand the problem.
Due to limitation of our environment only self-signed certs are used in labs :(

9. Tips: Apache configuration files
Example configuration tree
/etc/apache2/ (sometimes httpd)
├── apache2.conf (general conf, not many actual directives here)
├── conf.d (here goes real configuration)
│   ├── charset
│   ├── localized-error-pages
│   ├── other-vhosts-access-log
│   └── security
├── envvars
├── magic
├── mods-available
│   ├── actions.conf
/../
│   ├── php5.conf
│   └── vhost_alias.load
├── mods-enabled
│   ├── php5.conf -> ../mods-available/php5.conf
│   ├── php5.load -> ../mods-available/php5.load
│   └── status.load -> ../mods-available/status.load
├── ports.conf (here goes your Listen directive)
├── sites-available
│   ├── default
│   ├── default-ssl
│   └── portal.conf
└── sites-enabled
└── 000-quake -> ../sites-available/portal.conf

10. Some more tips to help you
To use a feature, appropriate module must be loaded
Good practice is to use <IfModule>
Modules can be enabled via manual symlinking or use utility a2enmod
sometimes you need to install module first with apt
Sites can be enabled via manual symlinking or use utility a2enmod
As usual to services of UNIX-like systems Apache will not re-read the .conf files after the Web server starts running.
usually „service apache2 reload“ is enough to re-read and activate new configuration but not always. Restart always works.
apachectl is another useful utility for admin, check it out
Use official documentation from that corresponds your server version. DO NOT trust any crap you can google out.
Wish you success with your lab