5 The SQL module is composed of two parts: a generic SQL front-end
6 (rlm_sql), and a series of database-dependent back-end drivers,
7 (rlm_sql_mysql, rlm_sql_postgresql, etc.)
9 In order to build the drivers, you MUST ALSO install the development
10 versions of the database. That is, you must have the appropriate
11 header files and client libraries for (say) MySQL. The
12 rlm_sql_mysql driver is NOT a complete MySQL client implementation.
13 Instead, it is a small 'shim' between the FreeRADIUS rlm_sql module,
14 and the MySQL client libraries.
17 In general, the SQL schemas mirror the layout of the 'users' file.
18 So for configuring check items and reply items, see 'man 5 users',
19 and the examples in the 'users' file.
24 The SQL module employs two sets of check and reply item tables for
25 processing in the authorization stage. One set of tables (radcheck and
26 radreply) are specific to a single user. The other set of tables
27 (radgroupcheck and radgroupreply) is used to apply check and reply items
28 to users that are members of a certain SQL group. The usergroup table
29 provides the list of groups each user is a member of along with a priority
30 field to control the order in which groups are processed.
32 When a request comes into the server and is processed by the SQL module,
33 the flow goes something like this:
35 1. Search the radcheck table for any check attributes specific to the user
36 2. If check attributes are found, and there's a match, pull the reply items
37 from the radreply table for this user and add them to the reply
38 3. Group processing then begins if any of the following conditions are met:
39 a. The user IS NOT found in radcheck
40 b. The user IS found in radcheck, but the check items don't match
41 c. The user IS found in radcheck, the check items DO match AND
42 the read_groups directive is set to 'yes'
43 4. If groups are to be processed for this user, the first thing that is
44 done is the list of groups this user is a member of is pulled from the
45 usergroup table ordered by the priority field. The priority field of
46 the usergroup table allows us to control the order in which groups are
47 processed, so that we can emulate the ordering in the users file. This
48 can be important in many cases.
49 5. For each group this user is a member of, the corresponding check items
50 are pulled from radgroupcheck table and compared with the request. If
51 there is a match, the reply items for this group are pulled from the
52 radgroupreply table and applied.
53 6. Processing continues to the next group IF:
54 a. There was not a match for the last group's check items
55 (The above is exactly the same as in the users file)
56 7. Finally, if the user has a User-Profile attribute set or the Default
57 Profile option is set in the sql.conf, then steps 4-6 are repeated for
58 the groups that the profile is a member of.
60 A web page with some helpful documentation is:
62 http://www.frontios.com/freeradius.html
64 NOTE: this page may be slightly out of date when dealing with the database
70 One of the fields of the SQL schema is named 'op' This is for the
71 'operator' used by the attributes. e.g.:
73 Framed-IP-Address = 1.2.3.4
74 ^ ATTRIBUTE ----^ ^ OP ^ VALUE
76 If you want the server to be completely misconfigured, and to never
77 do what you want, leave the 'op' field blank. If you want to be
78 rudely told to RTFM, then post questions on the mailing list, asking
80 "why doesn't my SQL configuration work when I leave the 'op' field empty?"
83 The short answer is that with the op field empty, the server does
84 not know what you want it to do with the attribute. Should it be
85 added to the reply? Maybe you wanted to compare the operator to one
86 in the request? The server simply doesn't know.
88 So put a value in the field. The value is the string form of the
89 operator: "=", ">=", etc. See Section 4, below, for more details.
92 3. Authentication versus Authorization
94 Many people ask if they can "authenticate" users to their SQL
95 database. The answer to this question is "You're asking the wrong
98 An SQL database stores information. An SQL database is NOT an
99 authentication server. The ONLY users who should be able to
100 authenticate themselves to the database are the people who
101 administer it. Most administrators do NOT want every user to be
102 able to access the database, which means that most users will not be
103 able to "authenticate" themselves to the database.
105 Instead, the users will have their authorization information (name,
106 password, configuration) stored in the database. The configuration
107 files for FreeRADIUS contain a username and password used to
108 authenticate FreeRADIUS to the SQL server. (See raddb/sql.conf).
109 Once the FreeRADIUS authentication server is connected to the SQL
110 database server, then FreeRADIUS can pull user names and passwords
111 out of the database, and use that information to perform the
116 The list of operators is given below.
118 Op Example and documentation
119 -- -------------------------
121 = "Attribute = Value"
123 Not allowed as a check item for RADIUS protocol attributes. It is
124 allowed for server configuration attributes (Auth-Type, etc), and sets
125 the value of on attribute, only if there is no other item of the
128 As a reply item, it means "add the item to the reply list, but
129 only if there is no other item of the same attribute."
132 := "Attribute := Value"
134 Always matches as a check item, and replaces in the
135 configuration items any attribute of the same name. If no
136 attribute of that name appears in the request, then this
139 As a reply item, it has an identical meaning, but for the
140 reply items, instead of the request items.
142 == "Attribute == Value"
144 As a check item, it matches if the named attribute is present
145 in the request, AND has the given value.
147 Not allowed as a reply item.
150 += "Attribute += Value"
152 Always matches as a check item, and adds the current attribute
153 with value to the list of configuration items.
155 As a reply item, it has an identical meaning, but the
156 attribute is added to the reply items.
159 != "Attribute != Value"
161 As a check item, matches if the given attribute is in the
162 request, AND does not have the given value.
164 Not allowed as a reply item.
167 > "Attribute > Value"
169 As a check item, it matches if the request contains an
170 attribute with a value greater than the one given.
172 Not allowed as a reply item.
175 >= "Attribute >= Value"
177 As a check item, it matches if the request contains an
178 attribute with a value greater than, or equal to the one
181 Not allowed as a reply item.
183 < "Attribute < Value"
185 As a check item, it matches if the request contains an
186 attribute with a value less than the one given.
188 Not allowed as a reply item.
191 <= "Attribute <= Value"
193 As a check item, it matches if the request contains an
194 attribute with a value less than, or equal to the one given.
196 Not allowed as a reply item.
199 =~ "Attribute =~ Expression"
201 As a check item, it matches if the request contains an
202 attribute which matches the given regular expression. This
203 operator may only be applied to string attributes.
205 Not allowed as a reply item.
208 !~ "Attribute !~ Expression"
210 As a check item, it matches if the request contains an
211 attribute which does not match the given regular expression.
212 This operator may only be applied to string attributes.
214 Not allowed as a reply item.
217 =* "Attribute =* Value"
219 As a check item, it matches if the request contains the named
220 attribute, no matter what the value is.
222 Not allowed as a reply item.
225 !* "Attribute !* Value"
227 As a check item, it matches if the request does not contain
228 the named attribute, no matter what the value is.
230 Not allowed as a reply item.
234 Just like any other module, multiple instances of the rlm_sql
235 module can be defined and used wherever you like.
237 The default .conf files for the different database types,
238 contain 1 instance without a name like so:
243 You can create multiple named instances like so:
251 And then you can use a specific instance in radiusd.conf, like