After defining the Server Name, Webmaster
email address, and Available
Addresses, click the Virtual Hosts tab
and click the Edit Default Settings button. A
window as shown in Figure 25-3
appears. Configure the default settings for your Web server in this
window. 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 default values for the Directory Page Search
List and Error Pages work for
most servers. If you are unsure of these settings, do not modify
them.
The entries listed in the Directory Page Search
List define the DirectoryIndex
directive. 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
https://www.example.com/this_directory/,
they are going to get either the DirectoryIndex
page, if it exists, or a server-generated directory list. The server
tries to find one of the files listed in the DirectoryIndex
directive and returns 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 generates
and returns a list, in HTML format, of the subdirectories and files in
the directory.
Use the Error Code section to configure Apache HTTP Server
to redirect the client to a local or external URL in the event of a
problem or error. This option corresponds to the ErrorDocument
directive. If a problem or error occurs when a client tries to connect
to the Apache HTTP Server, the default action is to display the short error
message shown in the Error Code column. To
override this default configuration, select the error code and click
the Edit button. Choose
to display the default short error
message. Choose to redirect the client
to an external URL and enter a complete URL, including the
https://, in the Location
field. Choose to redirect the client
to an internal URL and enter a file location under the document root
for the Web server. The location must begin the a slash (/) and be
relative to the Document Root.
For example, to redirect a 404 Not Found error code to a webpage that you
created in a file called 404.html, copy
404.html to
DocumentRoot/../error/404.html.
In this case, DocumentRoot is the Document Root
directory that you have defined (the default is
/var/www/html/). If the Document Root is left as the
default location, the file should be copied to
/var/www/error/404.html. Then, choose
as the Behavior for 404 - Not
Found error code and enter /error/404.html
as the .
From the Default Error Page Footer menu, you can
choose one of the following options:
Show footer with email address —
Display the default footer at the bottom of all error pages
along with the email address of the website maintainer specified
by the ServerAdmin
directive. Refer to Section 25.3.1.1 General Options for information
about configuring the ServerAdmin directive.
Show footer — Display just the
default footer at the bottom of error pages.
No footer — Do not display a footer
at the bottom of error pages.
Use the Logging tab to configure options for
specific transfer and error logs.
By default, the server writes the transfer log to the
/var/log/httpd/access_log file and the error log
to the /var/log/httpd/error_log file.
The transfer log contains a list of all attempts to access the Web
server. It records the IP address of the client that is attempting to
connect, the date and time of the attempt, and the file on the Web
server that it is trying to retrieve. Enter the name of the path and
file in which to store this information. If the path and file name do
not start with a slash (/), the path is relative to the server root
directory as configured. This option corresponds to the TransferLog
directive.
You can configure a custom log format by checking Use custom
logging facilities and entering a custom log string in
the Custom Log String field. This configures
the LogFormat
directive. Refer to https://httpd.apache.org/docs-2.0/mod/mod_log_config.html#formats
for details on the format of this directive.
The error log contains a list of any server errors that occur. Enter
the name of the path and file in which to store this information. If
the path and file name do not start with a slash (/), the path is
relative to the server root directory as configured. This option
corresponds to the ErrorLog
directive.
Use the Log Level menu to set the verbosity of
the error messages in the error logs. It can be set (from least
verbose to most verbose) to emerg, alert, crit, error, warn, notice,
info or debug. This option corresponds to the LogLevel
directive.
The value chosen with the Reverse DNS Lookup menu
defines the HostnameLookups
directive. Choosing No Reverse Lookup sets the
value to off. Choosing Reverse Lookup sets the
value to on. Choosing Double Reverse Lookup sets
the value to double.
If you choose Reverse Lookup, your server
automatically resolves the IP address for each connection which
requests a document from your Web server. Resolving the IP address
means that your server makes one or more connections to the DNS in
order to find out the hostname that corresponds to a particular IP
address.
If you choose Double Reverse Lookup, your server
performs a double-reverse DNS. In other words, after a reverse
lookup is performed, a forward lookup is performed on the result. At
least one of the IP addresses in the forward lookup must match the
address from the first reverse lookup.
Generally, you should leave this option set to No Reverse
Lookup, because the DNS requests add a load to your server
and may slow it down. If your server is busy, the effects of trying
to perform these reverse lookups or double reverse lookups may be
quite noticeable.
Reverse lookups and double reverse lookups are also an issue for the
Internet as a whole. Each individual connection made to look
up each hostname adds up. Therefore, for your own Web server's
benefit, as well as for the Internet's benefit, you should leave this
option set to No Reverse Lookup.
Use the Environment tab to configure options for
specific variables to set, pass, or unset for CGI scripts.
Sometimes it is necessary to modify environment variables for CGI
scripts or server-side include (SSI) pages. The Apache HTTP Server can use the
mod_env module to configure the environment
variables which are passed to CGI scripts and SSI pages. Use the
Environment Variables page to configure the
directives for this module.
Use the Set for CGI Scripts section to set an
environment variable that is passed to CGI scripts and SSI pages. For
example, to set the environment variable MAXNUM
to 50, click the Add
button inside the Set for CGI Script section, as
shown in Figure 25-5, and type
MAXNUM in the Environment
Variable text field and 50 in the
Value to set text field. Click
OK to add it to the list. The Set for
CGI Scripts section configures the SetEnv
directive.
Use the Pass to CGI Scripts section to pass the
value of an environment variable when the server is first started to
CGI scripts. To see this environment variable, type the command
env at a shell prompt. Click the
Add button inside the Pass to CGI
Scripts section and enter the name of the environment
variable in the resulting dialog box. Click OK
to add it to the list. The Pass to CGI Scripts
section configures the PassEnv
directive.
To remove an environment variable so that the value is not
passed to CGI scripts and SSI pages, use the Unset for CGI
Scripts section. Click Add in the
Unset for CGI Scripts section, and enter the name
of the environment variable to unset. Click OK
to add it to the list. This corresponds to the UnsetEnv
directive.
To edit any of these environment values, select it from the list and
click the corresponding Edit button. To delete
any entry from the list, select it and click the corresponding
Delete button.
To learn more about environment variables in the Apache HTTP Server, refer to the
following:
Use the Directories page in the
Performance tab to configure options for
specific directories. This corresponds to the <Directory>
directive.
Click the Edit button in the top right-hand
corner to configure the Default Directory Options
for all directories that are not specified in the
Directory list below it. The options that you
choose are listed as the Options
directive within the
<Directory> directive. You can
configure the following options:
ExecCGI — Allow execution of CGI
scripts. CGI scripts are not executed if this option is not
chosen.
FollowSymLinks — Allow symbolic links
to be followed.
Includes — Allow server-side
includes.
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.
Multiview — Support
content-negotiated multiviews; this option is disabled by
default.
SymLinksIfOwnerMatch — Only follow
symbolic links if the target file or directory has the same
owner as the link.
To specify options for specific directories, click the
Add button beside the
Directory list box. A window as shown in Figure 25-7 appears. Enter the directory to
configure in the Directory text field at the
bottom of the window. Select the options in the right-hand list and
configure the Order
directive with the left-hand side options. The
Order directive controls the order in which allow
and deny directives are evaluated. In the Allow hosts
from and Deny hosts from text field,
you can specify one of the following:
Allow all hosts — Type all to
allow access to all hosts.
Partial domain name — Allow all hosts whose names match
or end with the specified string.
Full IP address — Allow access to a specific IP
address.
A subnet — Such as
192.168.1.0/255.255.255.0
A network CIDR specification — such as
10.3.0.0/16
If you check the Let .htaccess files override directory
options, the configuration directives in the
.htaccess file take precedence.
