<AuthBy UNIX> authenticates users from a user database stored in
a standard Unix password file or similar format. It is implemented in
AuthUNIX.pm
. It does not log (but does reply to)
accounting requests. For more information about the file format, see
Section 9.4. Unix password file. Since
Unix password files only have encrypted passwords, <AuthBy UNIX> can
not work with CHAP or MSCHAP authentication.
For performance reasons, <AuthBy UNIX> opens and reads the
password and group files at start-up, reinitialisation and whenever the
file modification times change, (i.e. they are cached within Radiator).
Since these files are cached in memory, large password files can require
large amounts of memory. If you set the Nocache parameter, the files will
be reread for every authentication, and will not be cached internally
(this can be slow if you have a large password or group files, and should
rarely be necessary).
It is not necessary to be running on a Unix host in order to use
<AuthBy UNIX>. It will work equally well on Windows and NT, but you
are probably less likely to need it there.
By using the Match parameter you can also specify other file formats if
you need to.
When attempting to authenticate a user, <AuthBy UNIX> will
encrypt the password from the user and compare it to the one in the
password file. If the encrypted passwords match, AuthBy UNIX will reply
with an Access-Accept message. If the user does not appear in the password
file, an Access-Reject message is sent to the client. <AuthBy UNIX>
caches the password file and group file internally, and rereads the files
when the modification time changes. If the Nocache parameter is set the
password and group files will be reread for every authentication.
It is important to note that on its own, <AuthBy UNIX> does not
implement check or reply items, and therefore can only be used for
“Authenticate only” applications. However, you can use it in conjunction
with another AuthBy module that does use check and reply items. For more
information, see
Section 7. Check and reply items. If you do this, you
can also use the Group check item, which will check whether the user is a
member of a group defined in the GroupFilename file.
Tip
You can use AddToReply to easily add standard reply items
to all users authenticated by <AuthBy UNIX>. For more information
see
Section 3.14.20. AddToReply