Apache HTTP Server Version 2.0
Apache HTTP Server Version 2.0
This document refers to the 2.0 version of Apache httpd, which is no longer maintained. Upgrade, and refer to the current version of httpd instead, documented at:
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| Description: | User authentication using MD5 Digest Authentication. |
|---|---|
| Status: | Experimental |
| Module Identifier: | auth_digest_module |
| Source File: | mod_auth_digest.c |
This module implements HTTP Digest Authentication. However, it has not been extensively tested and is therefore marked experimental.
AuthDigestAlgorithm AuthDigestDomain AuthDigestFile AuthDigestGroupFile AuthDigestNcCheck AuthDigestNonceFormat AuthDigestNonceLifetime AuthDigestQop AuthDigestShmemSize
Using MD5 Digest authentication is very simple. Simply set
up authentication normally, using AuthType Digest and
AuthDigestFile instead
of the normal AuthType Basic and AuthUserFile; also, replace any AuthGroupFile with AuthDigestGroupFile. Then add a
AuthDigestDomain directive
containing at least the root URI(s) for this protection space.
Appropriate user (text) files can be created using the
htdigest tool.
<Location /private/>
AuthType Digest
AuthName "private area"
AuthDigestDomain /private/ http://mirror.my.dom/private2/
AuthDigestFile /web/auth/.digest_pw
Require valid-user
</Location>
Digest authentication provides a more secure password system than Basic authentication, but only works with supporting browsers. As of November 2002, the major browsers that support digest authentication are Opera, MS Internet Explorer (fails when used with a query string - see "Working with MS Internet Explorer" below for a workaround), Amaya, Mozilla and Netscape since version 7. Since digest authentication is not as widely implemented as basic authentication, you should use it only in controlled environments.
The Digest authentication implementation in previous Internet
Explorer for Windows versions (5 and 6) had issues, namely that
GET requests with a query string were not RFC compliant.
There are a few ways to work around this issue.
The first way is to use POST requests instead of
GET requests to pass data to your program. This method
is the simplest approach if your application can work with this
limitation.
Since version 2.0.51 Apache also provides a workaround in the
AuthDigestEnableQueryStringHack environment variable.
If AuthDigestEnableQueryStringHack is set for the
request, Apache will take steps to work around the MSIE bug and
remove the query string from the digest comparison. Using this
method would look similar to the following.
BrowserMatch "MSIE" AuthDigestEnableQueryStringHack=On
This workaround is not necessary for MSIE 7, though enabling it does not cause any compatibility issues or significant overhead.
See the BrowserMatch
directive for more details on conditionally setting environment
variables
| Description: | Selects the algorithm used to calculate the challenge and response hases in digest authentication |
|---|---|
| Syntax: | AuthDigestAlgorithm MD5|MD5-sess |
| Default: | AuthDigestAlgorithm MD5 |
| Context: | directory, .htaccess |
| Override: | AuthConfig |
| Status: | Experimental |
| Module: | mod_auth_digest |
The AuthDigestAlgorithm directive
selects the algorithm used to calculate the challenge and response
hashes.
MD5-sess is not correctly implemented yet.
| Description: | URIs that are in the same protection space for digest authentication |
|---|---|
| Syntax: | AuthDigestDomain URI [URI] ... |
| Context: | directory, .htaccess |
| Override: | AuthConfig |
| Status: | Experimental |
| Module: | mod_auth_digest |
The AuthDigestDomain directive allows
you to specify one or more URIs which are in the same protection
space (i.e. use the same realm and username/password info).
The specified URIs are prefixes, i.e. the client will assume
that all URIs "below" these are also protected by the same
username/password. The URIs may be either absolute URIs (i.e.
including a scheme, host, port, etc) or relative URIs.
This directive should always be specified and
contain at least the (set of) root URI(s) for this space.
Omitting to do so will cause the client to send the
Authorization header for every request sent to this
server. Apart from increasing the size of the request, it may
also have a detrimental effect on performance if AuthDigestNcCheck is on.
The URIs specified can also point to different servers, in which case clients (which understand this) will then share username/password info across multiple servers without prompting the user each time.
| Description: | Location of the text file containing the list of users and encoded passwords for digest authentication |
|---|---|
| Syntax: | AuthDigestFile file-path |
| Context: | directory, .htaccess |
| Override: | AuthConfig |
| Status: | Experimental |
| Module: | mod_auth_digest |
The AuthDigestFile directive sets the
name of a textual file containing the list of users and encoded
passwords for digest authentication. File-path is the
absolute path to the user file.
The digest file uses a special format. Files in this format
can be created using the htdigest utility found in
the support/ subdirectory of the Apache distribution.
| Description: | Name of the text file containing the list of groups for digest authentication |
|---|---|
| Syntax: | AuthDigestGroupFile file-path |
| Context: | directory, .htaccess |
| Override: | AuthConfig |
| Status: | Experimental |
| Module: | mod_auth_digest |
The AuthDigestGroupFile directive sets
the name of a textual file containing the list of groups and their
members (user names). File-path is the absolute path to
the group file.
Each line of the group file contains a groupname followed by a colon, followed by the member usernames separated by spaces. Example:
mygroup: bob joe anne
Note that searching large text files is very inefficient.
Make sure that the AuthGroupFile is stored
outside the document tree of the web-server; do not put it in
the directory that it protects. Otherwise, clients may be able
to download the AuthGroupFile.
| Description: | Enables or disables checking of the nonce-count sent by the server |
|---|---|
| Syntax: | AuthDigestNcCheck On|Off |
| Default: | AuthDigestNcCheck Off |
| Context: | server config |
| Status: | Experimental |
| Module: | mod_auth_digest |
| Description: | Determines how the nonce is generated |
|---|---|
| Syntax: | AuthDigestNonceFormat format |
| Context: | directory, .htaccess |
| Override: | AuthConfig |
| Status: | Experimental |
| Module: | mod_auth_digest |
| Description: | How long the server nonce is valid |
|---|---|
| Syntax: | AuthDigestNonceLifetime seconds |
| Default: | AuthDigestNonceLifetime 300 |
| Context: | directory, .htaccess |
| Override: | AuthConfig |
| Status: | Experimental |
| Module: | mod_auth_digest |
The AuthDigestNonceLifetime directive
controls how long the server nonce is valid. When the client
contacts the server using an expired nonce the server will send
back a 401 with stale=true. If seconds is
greater than 0 then it specifies the amount of time for which the
nonce is valid; this should probably never be set to less than 10
seconds. If seconds is less than 0 then the nonce never
expires.
| Description: | Determines the quality-of-protection to use in digest authentication |
|---|---|
| Syntax: | AuthDigestQop none|auth|auth-int [auth|auth-int] |
| Default: | AuthDigestQop auth |
| Context: | directory, .htaccess |
| Override: | AuthConfig |
| Status: | Experimental |
| Module: | mod_auth_digest |
The AuthDigestQop directive determines
the quality-of-protection to use. auth will only do
authentication (username/password); auth-int is
authentication plus integrity checking (an MD5 hash of the entity
is also computed and checked); none will cause the module
to use the old RFC-2069 digest algorithm (which does not include
integrity checking). Both auth and auth-int may
be specified, in which the case the browser will choose which of
these to use. none should only be used if the browser for
some reason does not like the challenge it receives otherwise.
auth-int is not implemented yet.
| Description: | The amount of shared memory to allocate for keeping track of clients |
|---|---|
| Syntax: | AuthDigestShmemSize size |
| Default: | AuthDigestShmemSize 1000 |
| Context: | server config |
| Status: | Experimental |
| Module: | mod_auth_digest |
The AuthDigestShmemSize directive defines
the amount of shared memory, that will be allocated at the server
startup for keeping track of clients. Note that the shared memory
segment cannot be set less than the space that is neccessary for
tracking at least one client. This value is dependant on your
system. If you want to find out the exact value, you may simply
set AuthDigestShmemSize to the value of
0 and read the error message after trying to start the
server.
The size is normally expressed in Bytes, but you
may let the number follow a K or an M to
express your value as KBytes or MBytes. For example, the following
directives are all equivalent:
AuthDigestShmemSize 1048576
AuthDigestShmemSize 1024K
AuthDigestShmemSize 1M