Apache2 - Ubuntu 7.x
Overview
The Apache2 web server is available in Ubuntu Linux.
To install Apache2...
sudo apt-get install apache2
To restart your web server...
sudo /etc/init.d/apache2 restart
Configuration
Apache is configured by placing directives in plain text configuration files. The main configuration file is apache2.conf.
Other configuration files may be added using the Include directive, and wildcards can be used to include many configuration files. Any directive may be placed in any of these configuration files.
Changes to the main configuration files are recognized by Apache2 when it is restarted.
The server also reads a file, mime.types, which contains mime document types. The filename is set by the TypesConfig directive.
The default Apache2 configuration file is...
/etc/apache2/apache2.conf
You can edit this file to configure the Apache2 server. You can configure the port number, document root, modules, log files, virtual hosts, etc.
Basic Settings
Apache2 ships with a single default virtual host (using the VirtualHost directive) which can be modified or used as-is if you have a single site.
To modify the default virtual host, edit...
/etc/apache2/sites-available/default
To configure a new virtual host or site, copy that file into the same directory with a new name. For example,...
sudo cp /etc/apache2/sites-available/default /etc/apache2/sites-available/mynewsite
Edit the new file to configure the new site using some of the directives described below.
The ServerAdmin directive specifies the email address to be advertised for the server's administrator. The default value is...
webmaster@localhost
Change this to an email address that is delivered to you. If your website has a problem, Apache2 will display an error message containing this email address to report the problem to. Find this directive in your site's configuration file in...
/etc/apache2/sites-available
The Listen directive specifies the port, and optionally the IP address, Apache2 should listen on. If the IP address is not specified, Apache2 will listen on all IP addresses assigned to the machine it runs on.
The default value for the Listen directive is 80. To cause Apache2 to listen only on your loopback interface, and make it unavailable on the internet, change this to 127.0.0.1:80. The Listen directive can be found and changed in its own file,...
/etc/apache2/ports.conf
The ServerName directive is optional and specifies what FQDN your site should answer to. The default virtual host has no ServerName directive specified, so it will respond to all requests that do not match a ServerName directive in another virtual host.
If you have just acquired the domain name skywayrocks.com and wish to host it on your Ubuntu server, the value of the ServerName directive in your virtual host configuration file should be skywayrocks.com. Add this directive to the new virtual host file you created earlier...
/etc/apache2/sites-available/mynewsite
You may also want your site to respond to www.skywayrocks.com, since many users will assume the www prefix is appropriate. Use the ServerAlias directive for this. You may also use wildcards in the ServerAlias directive. For example,...
ServerAlias *.skywayrocks.com
...will cause your site to respond to any domain request ending in "skywayrocks.com".
The DocumentRoot directive specifies where Apache should look for the files that make up the site. The default value is...
/var/www
No site is configured there, but if you uncomment the RedirectMatch directive in...
/etc/apache2/apache2.conf
...requests will be redirected to...
/var/www/apache2-default
...where the default Apache2 site awaits. Change this value in your site's virtual host file, and remember to create that directory if necessary!
The directory...
/etc/apache2/sites-available
...is not parsed by Apache2. Symbolic links in...
/etc/apache2/sites-enabled
...point to "available" sites. Use the a2ensite (Apache2 Enable Site) utility to create those symbolic links, like so...
sudo a2ensite mynewsite
...where your site's configuration file is...
/etc/apache2/sites-available/mynewsite
Similarly, the a2dissite utility should be used to disable sites.
Default Settings
This section explains configuration of the Apache2 server default settings. For example, if you add a virtual host, the settings you configure for the virtual host take precedence for that virtual host. For a directive not defined within the virtual host settings, the default value is used.
The DirectoryIndex is the default page served by the server when a user requests an index of a directory by specifying a forward slash (/) at the end of the directory name.
For example, when a user requests the page...
http://www.example.com/this_directory/
...they will get either the DirectoryIndex page if it exists, a server-generated directory list if it does not and the Indexes option is specified, or a Permission Denied page if neither is true. The server will try to find one of the files listed in the DirectoryIndex directive and will return the first one it finds. If it does not find any of these files and if Options Indexes is set for that directory, the server will generate and return a list, in HTML format, of the subdirectories and files in the directory. The default value, found in...
/etc/apache2/apache2.conf
...is...
index.html index.cgi index.pl index.php index.xhtml
Thus, if Apache2 finds a file in a requested directory matching any of these names, the first will be displayed.
The ErrorDocument directive allows you to specify a file for Apache to use for specific error events. For example, if a user requests a resource that does not exist, a 404 error will occur, and per Apache2's default configuration, the file...
/usr/share/apache2/error/HTTP_NOT_FOUND.html.var
...will be displayed. That file is not in the server's DocumentRoot, but there is an Alias directive in...
/etc/apache2/apache2.conf
...that redirects requests to the...
/error
...directory to...
/usr/share/apache2/error/
To see a list of the default ErrorDocument directives...
grep ErrorDocument /etc/apache2/apache2.conf
By default, the server writes the transfer log to the file...
/var/log/apache2/access.log
You can change this on a per-site basis in your virtual host configuration files with the CustomLog directive, or omit it to accept the default, specified in...
/etc/apache2/apache2.conf
You may also specify the file to which errors are logged, via the ErrorLog directive, whose default is...
/var/log/apache2/error.log
These are kept separate from the transfer logs to aid in troubleshooting problems with your Apache2 server. You may also specify the LogLevel (the default value is "warn") and the LogFormat. See...
/etc/apache2/apache2.conf
...for the default value.
Some options are specified on a per-directory basis rather than per-server. Option is one of these directives. A Directory stanza is enclosed in XML-like tags, like so:
<Directory /var/www/mynewsite>
...
</Directory>
The Options directive within a Directory stanza accepts one or more of the following values (among others), separated by spaces:
ExecCGI Allow execution of CGI scripts. CGI scripts are not executed if this option is not chosen. Most files should not be executed as CGI scripts. This would be very dangerous. CGI scripts should kept in a directory separate from and outside your DocumentRoot, and only this directory should have the ExecCGI option set. This is the default, and the default location for CGI scripts is...
/usr/lib/cgi-binTo enable cgi, in apache2.conf, add the following...
<Files ~ "^\.cgi"> Options +ExecCGI </Files>Includes Allow server-side includes. Server-side includes allow an HTML file to include other files. IncludesNOEXEC Allow server-side includes, but disable the #exec and #include commands in CGI scripts. Indexes Display a formatted list of the directory's contents, if no DirectoryIndex (such as index.html) exists in the requested directory. For security reasons, this should usually not be set, and certainly should not be set on your DocumentRoot directory. Enable this option carefully on a per-directory basis only if you are certain you want users to see the entire contents of the directory.
Multiview Support content-negotiated multiviews. This option is disabled by default for security reasons. SymLinksIfOwnerMatch Only follow symbolic links if the target file or directory has the same owner as the link.
Virtual Hosts Settings
Virtual hosts allow you to run different servers for different IP addresses, different host names, or different ports on the same machine. For example, you can run the website for...http://www.example.com
...and...
http://www.anotherexample.com
...on the same Web server using virtual hosts. This option corresponds to the directive...
<VirtualHost>
...for the default virtual host and IP-based virtual hosts. It corresponds to the directive...
<NameVirtualHost>
...for a name-based virtual host. The directives set for a virtual host only apply to that particular virtual host. If a directive is set server-wide and not defined within the virtual host settings, the default setting is used. For example, you can define a Webmaster email address and not define individual email addresses for each virtual host. Set the DocumentRoot directive to the directory that contains the root document (such as index.html) for the virtual host. The default DocumentRoot is...
/var/www
The ServerAdmin directive within the VirtualHost stanza is the email address used in the footer of error pages if you choose to show a footer with an email address on the error pages.
Server Settings
This section explains how to configure basic server settings.
Directive Description LockFile Set the path to the lockfile used when the server is compiled with either... USE_FCNTL_SERIALIZED_ACCEPT...or...
USE_FLOCK_SERIALIZED_ACCEPTIt must be stored on the local disk. It should be left to the default value unless the logs directory is located on an NFS share. If this is the case, the default value should be changed to a location on the local disk and to a directory that is readable only by root.
PidFile Set the file in which the server records its process ID (pid). This file should only be readable by root. In most cases, it should be left to the default value. User Set the userid used by the server to answer requests. This setting determines the server's access. Any files inaccessible to this user will also be inaccessible to your website's visitors. The default value for User is www-data.
Unless you know exactly what you are doing, do not set the User directive to root. Using root as the User will create large security holes for your Web server.
The Group directive is similar to the User directive. Group sets the group under which the server will answer requests. The default group is also www-data.
Apache Modules
Apache is a modular server. This implies that only the most basic functionality is included in the core server. Extended features are available through modules which can be loaded into Apache. By default, a base set of modules is included in the server at compile-time. If the server is compiled to use dynamically loaded modules, then modules can be compiled separately, and added at any time using the LoadModule directive. Otherwise, Apache must be recompiled to add or remove modules. Ubuntu compiles Apache2 to allow the dynamic loading of modules. Configuration directives may be conditionally included on the presence of a particular module by enclosing them in an Once you install the module, the module will be available in...
You can use the a2enmod command to enable a module. You can use the a2dismod command to disable a module. Once you enable the module, the module will be available in...
The mod_ssl module adds an important feature to the Apache2 server - the ability to encrypt communications. Thus, when your browser is communicating using SSL encryption, the prefix... https:// is used at the beginning of the Uniform Resource Locator (URL) in the browser navigation bar.
The mod_ssl module is available in apache2-common package. If you have installed this package, you can run the following command from a terminal prompt to enable the mod_ssl module:
To set up your secure server, use public key cryptography to create a public and private key pair. In most cases, you send your certificate request (including your public key), proof of your company's identity, and payment to a Certificate Authority (CA). The CA verifies the certificate request and your identity, and then sends back a certificate for your secure server.
Alternatively, you can create your own self-signed certificate. Note, however, that self-signed certificates should not be used in most production environments. Self-signed certificates are not automatically accepted by a user's browser. Users are prompted by the browser to accept the certificate and create the secure connection.
Once you have a self-signed certificate or a signed certificate from the CA of your choice, you need to install it on your secure server.
You need a key and a certificate to operate your secure server, which means that you can either generate a self-signed certificate or purchase a CA-signed certificate. A CA-signed certificate provides two important capabilities for your server:
Most Web browsers that support SSL have a list of CAs whose certificates they automatically accept. If a browser encounters a certificate whose authorizing CA is not in the list, the browser asks the user to either accept or decline the connection.
You can generate a self-signed certificate for your secure server, but be aware that a self-signed certificate does not provide the same functionality as a CA-signed certificate. A self-signed certificate is not automatically recognized by most Web browsers, and a self-signed certificate does not provide any guarantee concerning the identity of the organization that is providing the website. A CA-signed certificate provides both of these important capabilities for a secure server. The process of getting a certificate from a CA is fairly easy. A quick overview is as follows:
Whether you are getting a certificate from a CA or generating your own self-signed certificate, the first step is to generate a key.
To generate the Certificate Signing Request (CSR), you should create your own key. You can run the following command from a terminal prompt to create the key:
Generating RSA private key, 1024 bit long modulus
You can now enter your passphrase. For best security, it should at least contain eight characters. The minimum length when specifying -des3 is four characters. It should include numbers and/or punctuation and not be a word in a dictionary. Also remember that your passphrase is case-sensitive.
Re-type the passphrase to verify. Once you have re-typed it correctly, the server key is generated and stored in server.key file.
You can also run your secure web server without a passphrase. This is convenient because you will not need to enter the passphrase every time you start your secure web server. But it is highly insecure and a compromise of the key means a compromise of the server as well.
In any case, you can choose to run your secure web server without a passphrase by leaving out the -des3 switch in the generation phase or by issuing the following command at a terminal prompt:
Once you run the above command, the insecure key will be stored in the server.key.insecure file. You can use this file to generate the CSR without passphrase.
To create the CSR, run the following command at a terminal prompt:
It will prompt you enter the passphrase. If you enter the correct passphrase, it will prompt you to enter Company Name, Site Name, Email Id, etc. Once you enter all these details, your CSR will be created and it will be stored in the server.csr file. You can submit this CSR file to a CA for processing. The CAN will use this CSR file and issue the certificate. On the other hand, you can create self-signed certificate using this CSR.
To create the self-signed certificate, run the following command at a terminal prompt:
The above command will prompt you to enter the passphrase. Once you enter the correct passphrase, your certificate will be created and it will be stored in the server.crt file.
If your secure server is to be used in a production environment, you probably need a CA-signed certificate. It is not recommended to use self-signed certificate.
You can install the key file server.key and certificate file server.crt or the certificate file issued by your CA by running following commands at a terminal prompt:
You should add the following four lines to...
...or the configuration file for your secure virtual host. You should place them in the VirtualHost section. They should be placed under the DocumentRoot line:
SSLOptions +FakeBasicAuth +ExportCertData +CompatEnvVars +StrictRequire
SSLCertificateFile /etc/ssl/certs/server.crt
HTTPS should listen on port number 443. Edit...
...and add the following line...
Once you install your certificate, you should restart your web server. You can run the following command at a terminal prompt to restart your web server:
You should remember and enter the passphrase every time you start your secure web server.
You will be prompted to enter the passphrase. Once you enter the correct passphrase, the secure web server will be started. You can access the secure server pages by typing...
...in your browser address bar.
sudo apt-get install libapache2-mod-auth-mysql
/etc/apache2/mods-available
/etc/apache2/mods-enabled
HTTPS Configuration
sudo a2enmod ssl
Certificates and Security
Types of Certificates
Generating a Certificate Signing Request (CSR)
openssl genrsa -des3 -out server.key 1024
.....................++++++
.................++++++
unable to write 'random state'
e is 65537 (0x10001)
Enter pass phrase for server.key:
openssl rsa -in server.key -out server.key.insecure
openssl req -new -key server.key -out server.csr
Creating a Self-Signed Certificate
openssl x509 -req -days 365 -in server.csr -signkey server.key -out server.crt
Installing the Certificate
sudo cp server.crt /etc/ssl/certs
sudo cp server.key /etc/ssl/private
/etc/apache2/sites-available/default
SSLEngine on
SSLCertificateKeyFile /etc/ssl/private/server.key
/etc/apache2/ports.conf
Listen 443
Accessing the Server
sudo /etc/init.d/apache2 restart
https://your_hostname/url/
