Network Working Group Andy Bennett INTERNET-DRAFT Bernie Volz Process Software March 2000 Expires September 2000 DHCP Schema for LDAP Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. Abstract This document presents an LDAP schema to represent the configuration of the DHCP protocol within a TCP/IP network. It can be used to represent the configuration(s) of an entire enterprise network, a subset of the network, or even a single server. 1. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Bennett, et. al. Expires September 2000 [Page 1] Internet Draft DHCP Schema for LDAP March 2000 In places where different sets of terminology are commonly used to represent similar DHCP concepts, this schema uses the terminology of the Internet Software Consortium's DHCP server reference implementa- tion. For more information see www.isc.org. 2. Design Considerations Some of the design considerations for this schema were: o Heterogeneous server environment - This schema is not designed to represent the configuration of a specific DHCP server implementa- tion. The intent of this schema is to provide a basic framework for the representation of the most common elements used in the con- figuration of DHCP. This should allow other network services to obtain and use basic DHCP configuration information in a server- independent way. Also note that it is highly unlikely that this schema will be able to represent every feature of every implementa- tion (and it is not intended to do so). It is expected that some implementations may need to extend the schema objects in order to fully implement all their features. o Use of the schema - This draft does not define any "minimal compli- ance criteria" for using the schema. It is recommended that you use the object classes defined in this draft if you are represent- ing DHCP configuration information in an LDAP directory. Some implementations may choose not to support all of the objects defined here. In particular, the following two decisions are explicitly left up to the implementation: - it is up to the implementation to determine whether or not the lease information will be stored in the directory. Some imple- mentations may choose not to store this information. - it is up to the implementation to determine if the data in the directory is considered "authoritative", or if it is simply a copy of data from an authoritative source. o The schema is focused on the representation of configuration infor- mation. It does not provide for the representation of statistical data, or historical lease data, only the current state of the DHC protocol's configuration. o The information in this schema will be used primarily by two types of applications: DHCP servers (for loading their configuration) and Management Interfaces (for defining/editing configurations). The schema should must be efficient for the needs of both types of applications. Bennett, et. al. Expires September 2000 [Page 2] Internet Draft DHCP Schema for LDAP March 2000 o The schema is designed to allow objects managed by DHCP (such as computers, subnets, etc) to be present anywhere in a directory hierarchy (to allow those objects to be placed in the directory for managing administrative control and access to the objects). How- ever, the schema also provides for the possibility that any given object may have multiple sets of configuration parameters defined for different servers. o The schema uses a few naming conventions - all object classes and attributes are prefixed with "dhcp" and there are no object classes and attributes that have the same name. The schema also uses stan- dard naming attributes ("cn", "ou", etc) for all objects. In some cases it is recommended that the "cn" matches another attribute value. o Relationship to DEN/DMTF - This document takes into consideration the object-oriented information model for representing Network information (including DHCP information) currently under develop- ment as part of the Common Information Model (CIM) activity in the Distributed Management Task Force (DMTF). It should be noted that the CIM schema is still under development and subject to change. The DMTF efforts continue and draw upon the Directory-Enabled Net- works (DEN) specification. The schema described in this Internet- Draft is intended to be an LDAP implementation of the appropriate objects in the DMTF model. The DMTF schema was used as a source for defining certain terminology within this schema. For more information see [DMTF] and [DEN]. Prior versions of this draft included a mapping between the two schemas, but this has been removed since the DMTF schema is still under development. When it is complete a new draft may be published to document the mapping between the schemas. o Relationship to Policy Framework working group - Much of the infor- mation in this schema could be represented using the generalized schema being developed by the Policy Framework. However, there were two issues that we felt would make this a very complex and most likely inefficient representation: (1) the complexity of the inheritance relationships between the dhcp policy objects defined in this document and (2) the Policy Framework schema represents each of the conditions and actions of a policy as separate objects. However, it is still a fairly straightforward process to map the objects from this schema into the Policy Framework Core Schema objects. For more information see [POLICY]. 3. Common Attributes Although DHCP manages several different types of objects, the config- uration of those objects is often very similar. Consequently, most Bennett, et. al. Expires September 2000 [Page 3] Internet Draft DHCP Schema for LDAP March 2000 of these objects have a common set of attributes. The dhcpConfigurableObject class is an auxiliary class which can be used to associate the basic set of configuration attributes with another object. Since some directories do not provide auxiliary classes we have also repeated these common attributes in the defini- tion of each of the DHCP object class definitions. An implementation of this schema is not required to provide this aux- iliary object class, but it SHOULD provide it if auxiliary classes are supported. This is useful for associating DHCP configuration settings for objects that are not directly defined as part of this schema. 3.1. dhcpConfigurableObject Object Class NAME dhcpConfigurableObject DESCRIPTION A class that provides attributes for configuring options and server parameters for DHCP. TYPE Auxiliary DERIVED FROM Top POSSIBLE SUPERIORS ( ) MUST CONTAIN ( ) MAY CONTAIN ( dhcpOptionSetting dhcpParameterSetting dhcpFieldSetting dhcpForcedOptions dhcpIncludeOptionSet ) 3.2. Common Attribute Definitions NAME dhcpOptionSetting DESCRIPTION Encoded option values to be sent to clients. Each value represents a single option and contains (OptionTag, Length, OptionValue) encoded in the 16-bit format used by DHCP. For more information see [DHCPOPT]. SYNTAX OctetString MULTI-VALUE NAME dhcpParameterSetting DESCRIPTION Encoded values of parameters that control server behav- ior. Each value represents a single parameter setting in the form (ParameterName, ParameterValue) where the parameter name is a set of ASCII characters followed by a space followed by the parameter value as a string. SYNTAX IA5String MULTI-VALUE Bennett, et. al. Expires September 2000 [Page 4] Internet Draft DHCP Schema for LDAP March 2000 NAME dhcpFieldSetting DESCRIPTION Encoded settings of fields (such as siaddr, file) in the DHCP message whose values may be configurable for send- ing back to a client. For more information see [RFC951]. Encoded in the form (FieldName, FieldValue) where the field name is a set of ASCII characters fol- lowed by a space followed by the field value as a string. SYNTAX IA5String MULTI-VALUE NAME dhcpForcedOptions DESCRIPTION This is a list of DHCP option tags that MUST be sent to clients. If not specified, the server only sends the options back to the client which were requested. SYNTAX Integer MULTI-VALUE NAME dhcpIncludeOptionSet DESCRIPTION The distinguished name(s) of dhcpNamedOptionSet objects whose settings should be included for this object. If there are multiple option sets, the order is important so each value is preceded by it's precedence, followed by a colon as in "1:dn1", "2:dn2", etc. Settings defined on the object take precedence over any settings found in an included option set. SYNTAX IA5String MULTI-VALUE 4. Configurations and Services The DHC working group is currently considering several proposals for failover and redundancy of DHCP servers. These may require the shar- ing of configuration information between servers. This schema pro- vides a generalized mechanism for supporting any of these proposals, by separating the definition of a server from the definition of the configuration being provided by the server. By separating these two concepts, a configuration may be provided by one or by several servers, and similarly, a server may provide one or more configurations. The schema does allow for a server to be config- ured as either a primary or secondary provider of a configuration. Configurations are also defined so that one configuration can include some of the objects that are defined in another configuration (see "dhcpIncludeObjects" attribute). This allows for sharing and/or a hierarchy of related configuration items. Bennett, et. al. Expires September 2000 [Page 5] Internet Draft DHCP Schema for LDAP March 2000 4.1. dhcpService Object Class A "dhcpService" is a single instance of DHC server software running on a computer system that provides the DHCP service defined by a "dhcpConfiguration". NAME dhcpService DESCRIPTION This represents a single DHCP server. TYPE Structural DERIVED FROM Top POSSIBLE SUPERIORS ( ) MUST CONTAIN ( cn ) MAY CONTAIN ( dhcpConfigurationDn dhcpImplementation ) 4.1.1. dhcpService Attribute Definitions NAME cn DESCRIPTION The "common name" of the server. This does not have any significance to the server process that provides the DHCP service - it is simply a unique name used to refer to the server. This attribute should be used as the naming attribute when constructing the dn. NAME dhcpConfigurationDn DESCRIPTION The distinguished name(s) of the configurations provided by the server. SYNTAX DN MULTI-VALUE NAME dhcpImplementation DESCRIPTION This is a string value that identifies the hard- ware/software platform and version which is providing the service. SYNTAX IA5String SINGLE-VALUE 4.2. dhcpConfiguration Object Class A "dhcpConfiguration" is the collection of configuration information that represents everything a server would need to know to provide DHC service to some set of clients. From the perspective of the schema, it is basically a collection of objects. This object class is used to capture information common to all the objects in a configuration. The algorithm used to locate all the objects in a configuration is discussed later. Bennett, et. al. Expires September 2000 [Page 6] Internet Draft DHCP Schema for LDAP March 2000 NAME dhcpConfiguration DESCRIPTION This represents a configuration, or a collection of settings for related objects. A single ser- vice may have multiple configurations. A config- uration may be provided by multiple services, but only one can be primary. TYPE Structural DERIVED FROM Top POSSIBLE SUPERIORS ( ) MUST CONTAIN ( cn ) MAY CONTAIN ( dhcpPrimaryService dhcpSecondaryService dhcpIncludeObjects dhcpOptionSetting dhcpParameterSetting dhcpFieldSetting dhcpForcedOptions dhcpIncludeOptionSet ) 4.2.1. dhcpConfiguration Attribute Definitions NAME cn DESCRIPTION The "common name" of the configuration. This should be used as the naming attribute when constructing the dn. NAME dhcpPrimaryService DESCRIPTION The "dhcpService" which is the primary for the configu- ration. SYNTAX DN SINGLE-VALUE NAME dhcpSecondaryService DESCRIPTION The "dhcpService(s)" which provide backup for the con- figuration. SYNTAX DN MULTI-VALUE NAME dhcpIncludeObjects DESCRIPTION This attribute defines objects that are included in a configuration. Each value is an LdapURL [RFC2255] (specifying search criteria) that is evaluated to find other objects that are included in this configuration. Note that in addition to these objects, all objects that are children of the configuration object in the direc- tory are automatically included in the configuration. SYNTAX IA5String MULTI-VALUE 5. Objects that represent Assignment Rules Most of a DHCP configuration is the definition of rules that govern the assignment of DHCP options and addresses to clients. This schema defines a set of object classes which are common to most server implementations for defining these rules. All of these object classes are based on a higher level abstraction that represents a Bennett, et. al. Expires September 2000 [Page 7] Internet Draft DHCP Schema for LDAP March 2000 dhcp assignment rule. This is done for several reasons: it simplifies the organization of the data and it also facilitates the mapping of the dhcp schema to other schemas being developed in other working groups (see [POLICY] for example). This schema separates the definition of an assignment rule for an object from the object itself. This allows for the definition of multiple rules for a single object (possibly in different dhcp con- figurations). However, each assignment rule does maintain a link back to the definition of the object (see the "dhcpSourceObject" attribute). The structure of a "source object" is not defined in this schema. It can be any LDAP object, and it is not required to even exist. How- ever, if it does exist that object can use the "dhcpConfigurableOb- ject" auxiliary class to directly associate dhcp configuration infor- mation with that object. If an object is defined in this way, this information is used on every assignment rule that references the object. The assignment rule objects in the directory can be organized in a hierarchical fashion. If objects are organized this way, the "child" rule object inherits settings from the "parent" rule object. This can be done recursively. Furthermore, the "child" rule object inher- its any conditions from the "parent" rule as well. This means that the "child" rule's settings will only be used when both sets of con- ditions are met. As an example, if a "dhcpClass" is a child of a "dhcpSubnet" then the settings for that class will only be used if the client request is a member of that class AND it is also from the specified subnet. The algorithm for resolving which option settings are applied for a policy object is defined in a later section. 5.1. dhcpRule Object Class The "dhcpRule" class is an abstract class that defines attributes that are common to the DHCP configuration objects that define these rules. This class is the base class from which others are derived. Also note that it includes all the attributes from the dhcpConfigurableOb- ject class. Bennett, et. al. Expires September 2000 [Page 8] Internet Draft DHCP Schema for LDAP March 2000 NAME dhcpRule DESCRIPTION The base class for defining rules for address and option assignment. TYPE Abstract DERIVED FROM Top POSSIBLE SUPERIORS ( ) MUST CONTAIN ( cn dhcpRuleType ) MAY CONTAIN ( dhcpVendorCondition dhcpSourceObject dhcpOptionSetting dhcpParameterSetting dhcpFieldSetting dhcpForcedOptions dhcpIncludeOptionSet ) 5.2. dhcpRule Attribute Definitions NAME cn DESCRIPTION The "common name" of the rule. This should be used as the naming attribute when constructing the dn. NAME dhcpRuleType DESCRIPTION The type of assignment rule. This should be one of 'POOL', 'SUBNET', 'SHAREDNETWORK', 'CLIENT', 'CLASS' unless the server implementation extends this with a new type of rule. SYNTAX IA5String SINGLE-VALUE NAME dhcpVendorCondition DESCRIPTION If the server extends the rule types, this attribute MAY be used to specify the conditions under which the rule should be applied. The content of this attribute is defined by the vendor/server implementation. SYNTAX IA5String MULTI-VALUE NAME dhcpSourceObject DESCRIPTION If the rule applies to an object that is defined else- where in the directory, this attribute has the distin- guished name of that object. The source object SHOULD be a dhcpConfigurableObject. Also note that the source object is used to determine option & parameter settings (see the algorithm discussed later in this document). SYNTAX DN SINGLE-VALUE 5.3. dhcpPool Object Class A "dhcpPool" represents a rule for a collection of addresses speci- fied by one or more ranges of addresses. If there are multiple ranges specified, they do not need to be contiguous, and it is not required that all the addresses be contained on the same IP subnet. Bennett, et. al. Expires September 2000 [Page 9] Internet Draft DHCP Schema for LDAP March 2000 The "dhcpRuleType" attribute MUST be set to 'POOL', and the "cn" SHOULD be set to the value of the "dhcpPoolName" attribute". NAME dhcpPool DESCRIPTION This stores configuration information about one (or more) ranges of addresses. TYPE Structural DERIVED FROM dhcpRule POSSIBLE SUPERIORS ( OrganizationalUnit dhcpRule ) MUST CONTAIN ( cn dhcpPoolName dhcpAddressRange ) MAY CONTAIN ( ) 5.3.1. dhcpPool Attribute Definitions NAME dhcpPoolName DESCRIPTION A descriptive name of the pool. SYNTAX IA5String SINGLE-VALUE NAME dhcpAddressRange DESCRIPTION The starting & ending IP Addresses in the range (inclu- sive), separated by a hyphen; if the range only contains one address, then just the address can be specified with no hyphen. Each range is defined as a separate value. SYNTAX IA5String MULTI-VALUE 5.4. dhcpSubnet Object Class A "dhcpSubnet" represents an assignment rule for an IP subnet. The "dhcpRuleType" attribute MUST be set to 'SUBNET', and the "cn" SHOULD be set to the value of the "dhcpSubnetName" attribute". NAME dhcpSubnet DESCRIPTION This class defines a subnet. TYPE Structural DERIVED FROM dhcpRule POSSIBLE SUPERIORS ( OrganizationalUnit dhcpRule ) MUST CONTAIN ( cn dhcpSubnetAddress dhcpSubnetMaskLength dhcpSubnetName ) MAY CONTAIN ( ) 5.4.1. dhcpSubnet Attribute Definitions NAME dhcpSubnetAddress DESCRIPTION The network address for the subnet. SYNTAX IA5String SINGLE-VALUE Bennett, et. al. Expires September 2000 [Page 10] Internet Draft DHCP Schema for LDAP March 2000 NAME dhcpSubnetMaskLength DESCRIPTION The subnet mask length for the subnet. The mask can be easily computed from this length. SYNTAX Integer SINGLE-VALUE NAME dhcpSubnetName DESCRIPTION A descriptive name of the subnet. SYNTAX IA5String SINGLE-VALUE 5.5. dhcpSharedNetwork Object Class A "dhcpSharedNetwork" represents an assignment rule for multiple sub- nets on the same physical cabling. The "dhcpRuleType" attribute MUST be set to 'SHAREDNETWORK', and the "cn" SHOULD be set to the value of the "dhcpSharedNetworkName" attribute". NAME dhcpSharedNetwork DESCRIPTION This represents multiple subnets on the same physical cabling. TYPE Structural DERIVED FROM dhcpRule POSSIBLE SUPERIORS ( OrganizationalUnit dhcpRule ) MUST CONTAIN ( cn dhcpSharedNetworkName ) MAY CONTAIN ( ) 5.5.1. dhcpSharedNetwork Attribute Definitions NAME dhcpSharedNetworkName DESCRIPTION A descriptive name of the shared network. SYNTAX IA5String SINGLE-VALUE 5.6. dhcpClient Object Class The "dhcpClient" object class is used to store configuration informa- tion related to a specific host. The "dhcpRuleType" attribute MUST be set to 'CLIENT'. NAME dhcpClient DESCRIPTION This represents client-specific DHCP assignments. TYPE Structural DERIVED FROM dhcpRule POSSIBLE SUPERIORS ( OrganizationalUnit dhcpRule ) MUST CONTAIN ( cn dhcpClientIdentifier ) MAY CONTAIN ( dhcpClassMember dhcpReservedAddress ) Bennett, et. al. Expires September 2000 [Page 11] Internet Draft DHCP Schema for LDAP March 2000 5.6.1. dhcpClient Attribute Definitions NAME dhcpClientIdentifier DESCRIPTION A unique identifier for the client. This is encoded as follows: the first two octets represent a type and sub- type for the identifier. If the type field has a value of 0, then the subtype is a dhcp option tag, and the remainder of the octets are the value of that option to use as an id (represented as it would be sent using the DHCP protocol, including the bytes for the length). If the type field has a value of 1, then the subtype octet is the ARP hardware type (see [RFC2132]) and the remain- der of the bytes are the hardware address. Server implementations may choose to extend the set of types, but these two MUST be recognized. Note that a client can have more than one unique identifier specified - it is left to the server implementation to decide if one or all identifiers must be matched or which take precedence over others. SYNTAX OctetString MULTI-VALUE NAME dhcpClassMember DESCRIPTION This attribute indicates that the client is a member of the specified class(es). SYNTAX IA5String MULTI-VALUE NAME dhcpReservedAddress DESCRIPTION This attribute indicates the reserved (aka fixed) address(es) for this client (if there are any). There MAY be corresponding "dhcpAddress" objects created for tracking this reservation. SYNTAX IA5String MULTI-VALUE 5.7. dhcpClass Object Class A "dhcpClass" represents information about a collection of clients. The DHC protocol provides 2 mechanisms for managing this information (User Class and Vendor Class). The schema also provides 2 additional mechanisms for configuring groups of clients that are supported by some servers. Clients may be explicitly added to a class by setting the "dhcpClassMember" attribute in the "dhcpClient" object class. Some servers also support forms of dynamic class membership beyond the User Class and Vendor Class mechanisms - the "dhcpVendorCondi- tion" attribute allows for the definition of dynamic classes. The "dhcpRuleType" attribute MUST be set to 'CLASS', and the "cn" SHOULD be set to the value of the "dhcpClassName" attribute". Bennett, et. al. Expires September 2000 [Page 12] Internet Draft DHCP Schema for LDAP March 2000 NAME dhcpClass DESCRIPTION Represents information about a collection of related clients. TYPE Structural DERIVED FROM dhcpRule POSSIBLE SUPERIORS ( OrganizationalUnit dhcpRule ) MUST CONTAIN ( cn dhcpClassName dhcpClassType) MAY CONTAIN ( ) 5.7.1. dhcpClass Attribute Definitions NAME dhcpClassName DESCRIPTION A descriptive name for the class. SYNTAX IA5String SINGLE-VALUE NAME dhcpClassType DESCRIPTION This attribute indicates the type of the class. It should be one of 'USERCLASS', 'VENDORCLASS', 'STATIC' (the only members of the class are enumerated clients), 'DYNAMIC' (membership is determined by some vendor-spe- cific conditions). SYNTAX IA5String SINGLE-VALUE 6. Other Configuration objects Many server implementations provide other objects that simplify the configuration of the DHCP protocol. One example is the ability to assign a name to a group of option settings and then to refer to the entire group of settings by referencing the name. This is addressed by the "dhcpNamedOptionSet" object class. It is also fairly common for server implementations to allow users to extend the default set of options with site specific option defini- tions. This is addressed by the "dhcpDictionary" object class. This object class is also used to define the implementation-specific parameters (and their values) that can be specified in the "dhcpPa- rameterSetting" attribute. 6.1. dhcpNamedOptionSet Object Class A "dhcpNamedOptionSet" is an object class for associating a name with a collection of option settings. The entire set of options can be associated with a DHCP object by referring to the name. This allows a common set of option settings to be re-used without repeating the option settings on each configured object. To see how an option set is referenced, see the "dhcpIncludeOptionSet" attribute. Bennett, et. al. Expires September 2000 [Page 13] Internet Draft DHCP Schema for LDAP March 2000 NAME dhcpNamedOptionSet DESCRIPTION This is a named collection of settings for options and/or server parameters. TYPE Structural DERIVED FROM Top POSSIBLE SUPERIORS ( OrganizationalUnit ) MUST CONTAIN ( cn ) MAY CONTAIN ( dhcpOptionSetting dhcpParameterSetting dhcpFieldSetting dhcpForcedOptions dhcpIncludeOptionSet ) 6.1.1. dhcpDictionary Object Class "dhcpDictionary" objects define the options and/or parameters that can be set when configuring various DHCP entities. NAME dhcpDictionary DESCRIPTION This class defines an option or parameter that can have a value. TYPE Structural DERIVED FROM Top POSSIBLE SUPERIORS ( OrganizationalUnit ) MUST CONTAIN ( cn dhcpTag ) MAY CONTAIN ( dhcpDisplayName dhcpDataType dhcpDefault dhcpMultiValued dhcpLegalValues dhcpTypeRestriction dhcpImplementation ) 6.2. dhcpDictionary Attribute Definitions NAME cn DESCRIPTION The "common name" of the option or parameter. This will usually be the same as the "dhcpTag" attribute. SYNTAX Integer SINGLE-VALUE NAME dhcpTag DESCRIPTION A unique value that identifies an option or parameter and that is encoded in the values of the "dhcpOptionSet- ting" and "dhcpParameterSetting" attributes. For options this SHOULD be the numeric tag for the option (stored as a string). SYNTAX IA5String SINGLE-VALUE NAME dhcpDisplayName DESCRIPTION This is a string identifier for the option or parameter. This is intended for display by a management tool or GUI. SYNTAX IA5String SINGLE-VALUE Bennett, et. al. Expires September 2000 [Page 14] Internet Draft DHCP Schema for LDAP March 2000 NAME dhcpDataType DESCRIPTION The data type for values of this option. One of the following: 'INT8', 'INT16', 'INT32', 'UINT8', 'UINT16', 'UINT32' , 'ADDRESS', 'ADDRESS-MASK-PAIR', 'BOOLEAN', 'STRING', 'BINARY'. Other values may be specified if the server implementation provides them. SYNTAX IA5String SINGLE-VALUE NAME dhcpDefault DESCRIPTION Indicates the default value of a parameter or option definition in a dictionary object. This is encoded as it would be in the "dhcpOptionSetting" or "dhcpParame- terSetting" attribute. SYNTAX OctetString SINGLE-VALUE NAME dhcpMultiValued DESCRIPTION Indicates whether the parameter or option can have more than one value. SYNTAX Boolean SINGLE-VALUE NAME dhcpLegalValues DESCRIPTION The list of allowed values for the option or parameter. Each "legal value" is stored as a separate value for the attribute, and is encoded based on the "dhcpDataType" attribute setting. SYNTAX OctetString MULTI-VALUE NAME dhcpTypeRestriction DESCRIPTION This attribute is used to specify that the option or parameter should only be used with specific types of assignment rules. This is restricted to the same set of values as the "dhcpRuleType" attribute. If not speci- fied it is assumed that the definition applies to all types. SYNTAX IA5String MULTI-VALUE NAME dhcpImplementation DESCRIPTION This attribute is used to specify that the option or parameter should only be used with specific server implementations. If not specified it is assumed that the definition applies to all implementations. SYNTAX IA5String MULTI-VALUE 7. Tracking Addresses The behavior of a DHCP server is influenced by two factors - it's configuration and the current state of the addresses that have been assigned to clients. This schema defined a set of objects for Bennett, et. al. Expires September 2000 [Page 15] Internet Draft DHCP Schema for LDAP March 2000 storing the configuration of the server, and the following object class provides the ability to record how addresses are used. 7.1. dhcpAddress Object Class This class represents an IP address. It may or may not be leaseable, and the object may exist even though a lease is not currently active for the associated IP address. Note that this object class has some of the "Settings" attributes that are defined for the "dhcpConfigurableObject", but they are not used for configuration - only for tracking the settings that were assigned to the client. It is not required that the server implemen- tation record options that were offered to the client. NAME dhcpAddress DESCRIPTION This class represents an IP Address, which may or may not have been leased. TYPE Structural DERIVED FROM Top POSSIBLE SUPERIORS ( ) MUST CONTAIN ( cn dhcpAddressState ) MAY CONTAIN ( dhcpExpirationTime dhcpStartTimeOfState dhcpLastTransactionTime dhcpBootpFlag dhcpDomainName dhcpDnsStatus dhcpRequestedHostName dhcpAssignedHostName dhcpReservedForClient dhcpAssignedToClient dhcpRelayAgentInfo dhcpOptionSetting dhcpParameterSetting dhcpFieldSetting ) 7.2. dhcpAddress Attribute Definitions NAME cn DESCRIPTION The IP address, as a string. SYNTAX IA5String SINGLE-VALUE Bennett, et. al. Expires September 2000 [Page 16] Internet Draft DHCP Schema for LDAP March 2000 NAME dhcpAddressState DESCRIPTION This stores information about the current binding-status of an address. For dynamic addresses managed by DHCP, the values should be restricted to the states defined in the safe-failover draft: 'FREE', 'ACTIVE', 'EXPIRED', 'RELEASED', 'RESET', 'ABANDONED', 'BACKUP'. For more information on these states see [FAILOVR]. For other addresses, it SHOULD be one of the following: 'UNKNOWN', 'RESERVED' (an address that is managed by DHCP that is reserved for a specific client), 'RESERVED-ACTIVE' (same as reserved, but address is currently in use), 'ASSIGNED' (assigned manually or by some other mecha- nism), 'UNASSIGNED', 'NOTASSIGNABLE'. SYNTAX IA5String SINGLE-VALUE NAME dhcpExpirationTime DESCRIPTION This is the time the current lease for an address expires. SYNTAX DateTime SINGLE-VALUE NAME dhcpStartTimeOfState DESCRIPTION This is the time of the last state change for a leased address. SYNTAX DateTime SINGLE-VALUE NAME dhcpLastTransactionTime DESCRIPTION This is the last time a valid DHCP packet was received from the client. SYNTAX DateTime SINGLE-VALUE NAME dhcpBootpFlag DESCRIPTION This indicates whether the address was assigned via BOOTP SYNTAX Boolean SINGLE-VALUE NAME dhcpDomainName DESCRIPTION This is the name of the domain sent to the client by the server. It is essentially the same as the value for DHCP option 15 sent to the client, and represents only the domain - not the full FQDN. To obtain the full FQDN assigned to the client you must prepend the "dhcpAs- signedHostName" to this value with a ".". SYNTAX IA5String SINGLE-VALUE Bennett, et. al. Expires September 2000 [Page 17] Internet Draft DHCP Schema for LDAP March 2000 NAME dhcpDnsStatus DESCRIPTION This indicates the status of updating DNS resource records on behalf of the client by the DHCP server for this address. The value is a 16-bit bitmask that has the same values as specified by the Failover-DDNS option (see [FAILOVR]). SYNTAX Integer SINGLE-VALUE NAME dhcpRequestedHostName DESCRIPTION This is the hostname that was requested by the client. SYNTAX IA5String SINGLE-VALUE NAME dhcpAssignedHostName DESCRIPTION This is the actual hostname that was assigned to a client. It may not be the name that was requested by the client. The fully qualified domain name can be deter- mined by appending the value of "dhcpDomainName" (with a dot separator) to this name. SYNTAX IA5String SINGLE-VALUE NAME dhcpReservedForClient DESCRIPTION The distinguished name of a "dhcpClient" that an address is reserved for. This may not be the same as the "dhc- pAssignedToClient" attribute if the address is being reassigned but the current lease has not yet expired. SYNTAX DN SINGLE-VALUE NAME dhcpAssignedToClient DESCRIPTION This is the distinguished name of a "dhcpClient" that an address is currently assigned to. This only has a value when the address is leased. SYNTAX DN SINGLE-VALUE NAME dhcpRelayAgentInfo DESCRIPTION If the client request was received via a relay agent, this contains information about the relay agent that was available from the DHCP request. This is a hex-encoded option value. For more information see [AGENT]. SYNTAX OctetString SINGLE-VALUE 8. Object Containment These diagrams depict the containment hierarchy of the objects. can be any LDAP object. Bennett, et. al. Expires September 2000 [Page 18] Internet Draft DHCP Schema for LDAP March 2000 | +---dhcpConfiguration | +--- ou = OptionDictionary | | | +---dhcpDictionary | +--- ou = ParameterDictionary | | | +---dhcpDictionary | +--- ou = NamedOptionSets | | | +---dhcpNamedOptionSet | +--- ou = Rules | | | +---dhcpRule | | | +---dhcpRule . . . | +--- ou = Addresses | +---dhcpAddress | +---dhcpService 9. Object Class Inheritance The following diagram shows the inheritance hierarchy of the classes: Bennett, et. al. Expires September 2000 [Page 19] Internet Draft DHCP Schema for LDAP March 2000 Top | +---dhcpDictionary | +---dhcpService | +---dhcpConfiguration (aux: dhcpConfigurableObject) | +---dhcpNamedOptionSet (aux: dhcpConfigurableObject) | +---dhcpAddress (aux: dhcpConfigurableObject) | +---dhcpRule (aux: dhcpConfigurableObject) | +---dhcpClass | +---dhcpClient | +---dhcpPool | +---dhcpSharedNetwork | +---dhcpSubnet 10. Determining Assignment Rule settings This section of the document defines the algorithm that should be used for determining the settings for options and/or parameters for an assignment rule. Most DHCP server implementations provide for some degree of inheritance of options between configuration objects. This algorithm is flexible enough to allow server implementations to represent their existing behavior. The option settings directly associated with a "dhcpRule" object MUST take precedence over all other option settings. The rule also inher- its options from the following objects (in order of precedence): - options from one or more included "dhcpNamedOptionSet" objects, as defined in the "dhcpIncludeOptionSet" attribute. If there is more than one option set, the attribute values define the order in which the option sets should be included. - options from the "dhcpSourceObject" for the rule. - options from "dhcpNamedOptionSet" objects associated with the "dhcpSourceObject" for the rule. - options from the "parent" rule (only if the object's parent in the directory is also a "dhcpRule" object. - options from "dhcpNamedOptionSet" objects associated with the "par- ent" rule. Bennett, et. al. Expires September 2000 [Page 20] Internet Draft DHCP Schema for LDAP March 2000 - options from walking up the directory hierarchy inheriting from ancestor rules until the "dhcpConfiguration" object is reached. 11. References [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC2132] Alexander, S., Droms, R., "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. [DMTF] Distributed Management Task Force, "Common Information Model (CIM) Specification", Version 2.0, Mar 1998. [DEN] Strassner, J., "Directory-Enabled Networks, Information Model and Base Schema", DEN Specification v3.0c, July 1998. [MSDHCP] Gu, Y., Vyaghrapuri, R., "An LDAP Schema for Dynamic Host Configuration Protocol Service", Internet Draft , August 1998. [NOVDHCP] Miller, T., Patel, A., Rao, P., "Lightweight Directory Access Protocol (v3): Schema for Dynamic Host Configuration Protocol (DHCP)", Internet Draft , June 1998. [FAILOVR] Droms, R., Rabil, G., Dooley, M., Kapur, A., Gonczi, S., Volz, B., "DHCP Failover Protocol", Internet Draft , October 1999. [AGENT] Patrick, M., "DHCP Relay Agent Information Option", Inter- net Draft , March 2000. [DHCPOPT] Carney, M., "New Option Review Guidelines and Additional Option Namespace", Internet Draft , Octo- ber 1999. [POLICY] Strassner, J., Elleson, E., Moore, B., "Policy Framework LDAP Core Schema", Internet Draft , November 1999. [RFC2251] Wahl, M., Howes, T., Kille, S., "Lightweight Directory Access Protocol (v3)", RFC 2251, December 1997. [RFC2252] Wahl, M., Coulbeck, A., Howes, T., Kille, S., "Lightweight Directory Access Protocol (v3) Attribute Syntax Defini- tions", RFC 2252, December 1997. [RFC2255] Howes, T., Smith, M., "The LDAP URL Format", RFC 2255, December 1997. [RFC951] Croft, B., Gilmore, J., "Bootstrap Protocol (BOOTP)", RFC 951, September 1985. [RFC2119] Bradner, S. "Key words for use in RFCs to Indicate Require- ment Levels", RFC 2119, March 1997. 12. Acknowledgements This document is closely aligned with the work being done in the Distributed Management Task Force (DMTF) Networks working group. Bennett, et. al. Expires September 2000 [Page 21] Internet Draft DHCP Schema for LDAP March 2000 Design ideas included in this document are primarily based on dis- cussions during two meetings with some members of the IETF DHC Working Group and the DMTF Networks working group. The contribu- tions of these individuals is gratefully acknowledged. Special thanks to Andrea Westerinen, Lee Rafalow, Steve Gonczi, Steve Chirokas, Kim Kinnear, Ellen Stokes, Tom Miller, Ye Gu, Glenn Waters, Mike Carney, Ralph Droms, Greg Rabil, Ted Lemon and Steve Bazyl for their contributions. Thanks also to Ester Burwell, Andy Sudduth, Fred Hunter, Paul Rai- son, Josh Littlefield, Peter Heitman, Neil Russell and Linda Scobo for their participation in these meetings. 13. Author information Andy Bennett Bernie Volz Process Software Corporation 959 Concord St. Framingham, MA 01701 Phone: (508) 879-6994 Email: bennett@process.com Email: volz@process.com 14. Full Copyright Statement Copyright (C) The Internet Society (1999). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into lan- guages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET Bennett, et. al. Expires September 2000 [Page 22] Internet Draft DHCP Schema for LDAP March 2000 ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Bennett, et. al. Expires September 2000 [Page 23]