2 - Raspberry PI Community Projects

Apache is a modular server, and many features are implemented by external modules that the
main program loads during its initialization. The default configuration only enables the most
common modules, but enabling new modules is a simple matter of running a2enmod module; to
disable a module, the command is a2dismod module. These programs actually only create (or
delete) symbolic links in /etc/apache2/mods-enabled/, pointing at the actual files (stored in
/etc/apache2/mods-available/).
With its default configuration, the web server listens on port 80 (as configured in /etc/
apache2/ports.conf), and serves pages from the /var/www/ directory (as configured in /etc/
apache2/sites-enabled/000-default).
GOING FURTHER
Adding support for SSL
Apache 2.2 includes the SSL module required for secure HTTP (HTTPS) out
of the box. It just needs to be enabled with a2enmod ssl, then the required
directives have to be added to the configuration files. A configuration
example is provided in /usr/share/doc/apache2.2-common/examples/
apache2/extra/httpd-ssl.conf.gz.
➨ http://httpd.apache.org/docs/2.2/mod/mod_ssl.html
11.2.2. Configuring Virtual Hosts
A virtual host is an extra identity for the web server.
Apache considers two different kinds of virtual hosts: those that are based on the IP address (or
the port), and those that rely on the domain name of the web server. The first method requires
allocating a different IP address (or port) for each site, whereas the second one can work on a
single IP address (and port), and the sites are differentiated by the hostname sent by the HTTP
client (which only works in version 1.1 of the HTTP protocol — fortunately that version is old
enough that all clients use it already).
The (increasing) scarcity of IPv4 addresses usually favors the second method; however, it is
made more complex if the virtual hosts need to provide HTTPS too, since the SSL protocol hasn't
always provided for name-based virtual hosting; the SNI extension (Server Name Indication) that
allows such a combination is not handled by all browsers. When several HTTPS sites need to
run on the same server, they will usually be differentiated either by running on a different port
or on a different IP address (IPv6 can help there).
The default configuration for Apache 2 enables name-based virtual hosts (with the NameVirtu
alHost *:80 directive in the /etc/apache2/ports.conf file). In addition, a default virtual host
is defined in the /etc/apache2/sites-enabled/000-default file; this virtual host will be used if no
host matching the request sent by the client is found.
CAUTION
First virtual host
Requests concerning unknown virtual hosts will always be served by the first
defined virtual host, which is why we defined www.falcot.com first here.
Chapter 11 — Network Services: Postfix, Apache, NFS, Samba, Squid, LDAP
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