Cisco Network Registrar User's Guide, 6.2.1
20 - Policies and Options
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Configuring Policies and Options

Table Of Contents

Configuring Policies and Options

Configuring DHCP Policies

Types of Policies

Options Reply Processing

Creating and Applying DHCP Policies

Cloning a Policy

Setting DHCP Options for Policies

Adding Option Values

Adding Complex Values for Suboptions

Editing Embedded Policies

Creating DHCP Option Definition Sets and Option Definitions

Using Standard Option Definition Sets

Creating Custom Option Definitions

Creating Vendor-Specific Option Definitions

Option Definition Data Types and Repeat Counts

Adding Suboption Definitions

Importing and Exporting Option Definition Sets

Setting Option Values for Policies


Configuring Policies and Options


This chapter describes how to set up DHCP policies and options. Before clients can use DHCP for address assignment, you must add at least one scope (dynamic address pool) to the server. The policies and options are assigned to the scope.

Configuring DHCP Policies

Every DHCP scope must have one or more policies defined for it. Policies define lease duration, gateway routers, and other configuration parameters, in what are called DHCP options. Policies are especially useful if you have multiple scopes, because you need only define a policy once.

This section describes how you can define named policies with specific option definitions, or use system default or embedded policies.

Types of Policies

There are three types of policies—system default, named, and embedded:

System default (system_default_policy)—Provides a single location for setting default values on certain options for all scopes. Use the system default policy to define standard DHCP options that have common values for all clients on all the networks that the DHCP server supports. You can modify the system default options and their values. If you delete a system default policy, it reappears using its original list of DHCP options and their system-defined values (see Table 20-1).

Table 20-1 System Default Policy Option Values 

System Default Option
Predefined Value

all-subnets-local

False

arp-cache-timeout

60 seconds

broadcast-address

255.255.255.255

default-ip-ttl

64

default-tcp-ttl

64

dhcp-lease-time

604800 seconds (7d)

ieee802.3-encapsulation

False

interface-mtu

576 bytes

mask-supplier

False

max-dgram-reassembly

576 bytes

non-local-source-routing

False

path-mtu-aging-timeout

6000 seconds

path-mtu-plateau-tables

68, 296, 508, 1006, 1492, 2002, 4352, 8166, 17914, 32000

perform-mask-discovery

False

router-discovery

True

router-solicitation-address

224.0.0.2

tcp-keepalive-garbage

False

tcp-keepalive-interval

0 seconds

trailer-encapsulation

False


Named—Policies you explicitly define by name. Named policies are usually named after their associated scope or client grouping. For example, the policy might be assigned options that are unique to a subnet, such as for its routers, and then be assigned to the appropriate scope.

Network Registrar includes a policy named default when you install the DHCP server. The server assigns this policy to newly created scopes. You cannot delete this default policy.

Embedded—A policy embedded in (and limited to) a named scope, scope template, client, or client-class. An embedded policy is implicitly created (or removed) when you add (or remove) the corresponding object. Embedded policy options have no default values and are initially undefined.


Tip Be sure to save the object (scope, client, or client-class) for which you are creating or modifying an embedded policy. Not doing so is a common error when using the Web UI.


Options Reply Processing

To eliminate any conflicting option values that are set at these various levels, the Network Registrar DHCP server uses a local priority method. It adopts the more locally defined option values first, ignores the ones defined on a more global level, and includes any default ones not otherwise defined. Before returning option values to a DHCPv4 client, the server prioritizes the option values in this order:

1. Client embedded policy.

2. Client assigned policy.

3. Client-class embedded policy.

4. Client-class assigned policy.

5. Scope embedded policy for clients, or address block embedded policy for subnets.

6. Scope assigned policy for clients (or default policy if a named policy is not applied to the scope), or address block assigned policy for subnets.

7. Any remaining unfulfilled options in the system_default_policy.


Note DHCPv6 policy prioritization is different than that for DHCPv4. See the "DHCPv6 Policy Hierarchy" section.


The server then searches the policies, in order, for these BOOTP and DHCP attribute values and returns the first occurrence of these values in its reply packet:

packet-siaddr returned in the siaddr packet field

packet-file-name returned in the file field

packet-server-name returned in the sname field

Creating and Applying DHCP Policies

This section describes how to create a policy at the DHCP server level and then allow a specific scope or scopes to reference it. A policy can consist of a:

Name—Not case sensitive and must be unique.

The permanent-leases attribute—A permanent lease never expires.

Lease time—How long a client can use an assigned lease before having to renew the lease with the DHCP server (not available for an embedded policy). The default lease time for both system default and default policies is seven days (604800 seconds). A policy contains two lease times—the client lease time and the server lease time:

Client lease time—Determines how long the client believes its lease is valid.

Server lease time—Determines how long the server considers the lease valid. Note that the server lease time is independent of the lease's grace period. The server does not allocate the lease to another client until after the lease time and grace period expire.


Caution Although Network Registrar supports the use of two lease times for special situations, Cisco Systems generally recommends that you not use the server-lease-time attribute.

You can establish these two different lease times if you want to retain information about clients' DNS names and yet have them renew their leases frequently. When you use a single lease time and it expires, the server no longer keeps that client's DNS name. However, if you use a short client lease time and a longer server lease time, then the client information is retained even after the client's lease expires. (For more on leases, see "Managing Leases.")

Lease grace period—Time period after the lease expires that it is unavailable for reassignment (not available for an embedded policy).

DNS update configuration—A DNS update configuration specifies the type of DNS updates to perform, the zones involved, the DNS server to be updated, and the related security. The policy determines the forward and reverse DNS update configuration objects, and can also specify the forward zone to use if a DNS server hosts multiple zones. (For details on DNS update configurations, see the "Creating DNS Update Configurations" section.)

DHCP options—To add option values, see the "Setting DHCP Options for Policies" section. See also "DHCP Options" for the supported option types.

To create a DHCP policy:


Step 1 In the Web UI, click DHCP, then Policies to open the List DHCP Policies page (Figure 20-1).

Figure 20-1 List DHCP Policies Page (Local)

Step 2 The default and system_default_policy is already provided for you. In the Web UI, to add a named policy, click Add Policy to open the Add DHCP Policy page (Figure 20-2).

Figure 20-2 Add DHCP Policy Page (Local)

Step 3 In the Web UI, give the policy a unique name (required).

In the CLI, use policy name create to create the policy.

Step 4 In the Web UI, accept the offer timeout and grace period defaults, or set them differently (required).

In the CLI, use policy name set offer-timeout=value and policy name set grace-period=value to set these two values.

Step 5 Add the necessary DHCP options (see further in the "Setting DHCP Options for Policies" section). In the CLI, use policy name setOption. However:

To set the lease time:

In the Web UI, set the dhcp-lease-time (51) option.

In the CLI, use policy name setLeaseTime.

To set the subnet mask:

In the Web UI, set the subnet-mask (1) attribute, but also enable the get-subnet-mask-from-policy attribute for the DHCP server.

In the CLI, use a combination of policy name setOption subnet-mask value and dhcp enable get-subnet-mask-from-policy.

To remove the subnet mask from the policy, either unset the attribute or disable it.

To set vendor-specific options, see the "Creating Vendor-Specific Option Definitions" section.

In the CLI, to confirm the option settings, use policy name listOptions or policy name getOption.

Step 6 Set the policy attributes (in the CLI, use policy name set or enable). These attributes include:

Unavailable timeout—See the "Setting Timeouts for Unavailable Leases, Including Upgrades" section.

Inhibit all renews—See the "Inhibiting Lease Renewals" section.

Limitation count—See the "Using Expressions" section.

Use client IDs for reservations—See the "Overriding Client IDs" section.

Permanent leases (not recommended). In the CLI, use use policy name enable permanent-leases. Note that enabling permanent leases forces the dhcp-lease-time option (51) to be set to infinite.

DNS update settings—To set the DNS update configuration that determines which forward or reverse zones you want to include in a DNS update, set the following attributes:

forward-dnsupdate—Name of the update configuration for the forward zone. Note that you can thereby set different update configurations for forward and reverse zones.

forward-zone-name—If necessary, overrides the forward zone in the update configuration. Use this in case a DNS server is hosting multiple zones.

reverse-dnsupdate—Name of the update configuration for the reverse zone. If not set on any policy in the policy hierarchy applicable to the client's request (see the "Options Reply Processing" section), the DHCP server uses the forward-dnsupdate configuration.

Step 7 In the Web UI, click Add Policy.

Step 8 Reload the DHCP server.


Cloning a Policy

In the CLI, you can clone a policy from an existing one by using policy clone-name create clone=policy, and then make adjustments to the clone. For example:

nrcmd> policy cloned-policy create clone=example-policy-1 offer-timeout=4m 

Setting DHCP Options for Policies

DHCP options automatically supply DHCP clients with configuration parameters, such as domain, nameserver, and subnet router addresses (see further in the "Creating DHCP Option Definition Sets and Option Definitions" section).

Adding Option Values

You can view, set, unset, and edit DHCP option values. When you set an option value, the DHCP server replaces any existing value or creates a new one, as needed for the given option name. Network Registrar DHCP options are grouped into categories to aid you in identifying options that you must set in various usage contexts (Table B-10 describes the categories). You can create custom option definitions to simplify entering custom option values (see the "Creating Custom Option Definitions" section).

To add option values:


Step 1 In the Web UI, create a policy, as described in the "Creating and Applying DHCP Policies" section.

In the CLI:

To view option values, use policy name getOption and policy name listOptions.

To set option values, use policy name setOption option. When you set an option value, the DHCP server replaces any existing value or creates a new one, as needed, for the given option name.

To unset option values, use policy name unsetOption.

Step 2 In the Web UI, add DHCP options to the policy by clicking their numbers and names in the Number drop-down list. The choices indicate the data type of the option value (see the "Option Definition Data Types and Repeat Counts" section).


Tip You can sort the options by Name, Number, or (in the case of DHCPv4) Legacy (grouping).


Step 3 In the Web UI, add the appropriate option value in the Value field. The Web UI does error checking based on the value entered. For example, to add the lease time for the policy, click the [51] dhcp-lease-time (unsigned time) option in the Number drop-down list, then add a lease time value in the Value field. (Options do not have any default values.)


Tip If you are configuring an option on a policy while another user is editing the option definition, log out of the session and log back in to get the new option definition.


Step 4 In the Web UI, click Add Option for each option. You must supply a value or you cannot add the option.

Step 5 In the Web UI, click Add Policy.


Tip If you add new option values or edit existing ones, be sure to save the policy object by clicking Modify Policy.



Adding Complex Values for Suboptions

If you are adding more complex option values such as for suboptions, use a parenthesized string format. The format requires that you:

Enclose each option level (option, suboption, subsuboption) in parentheses.

Separate multiple values with commas.

Separate data fields for packed data (missing the suboption code or length) with semicolons.

For example, the cablelabs-client-configuration option (122) normally has 10 suboptions as well as some subsuboptions. This example shows the syntax to set the suboption 1, 2, 3, and 4 data values, and includes the two subsuboptions for suboption 3 and the three subsuboptions for suboption 4 (which are packed data and have no code numbers):

(primary-dhcp-server 1 10.1.1.10) 
(secondary-dhcp-server 2 10.2.2.10) 
(provisioning-server 3 (flag 59; provisioning-server 10:10:10:10)) 
(as-backoff-retry 4 (as-backoff-retry-initial-time-ms 10; 
as-backoff-retry-max-time 10s; as-backoff-retry-count 100)) 

The suboption name (such as primary-dhcp-server) is optional. Hence, it is often safer to use just the code number and data value (or just the data value for packed data) to minimize typographical errors and parsing failures. The compacted (and preferred) version of the previous example that strips out the suboption names is:

(1 10.1.1.10) (2 10.2.2.10) (3 (59;10:10:10:10)) (4 (10;10s;100)) 

Even if you use numerical code values, Network Registrar always includes the equivalent names when it displays the suboptions (see the "Creating DHCP Option Definition Sets and Option Definitions" section).

To include suboptions that include enterprise IDs (such as for option 125), use the following format, for example, when entering in the policy option value:

(enterprise-id 1((1 10.1.1.1) (2 10.2.2.2) (3 www.cisco.com))) 

The parentheses surround the enterprise ID itself, the suboptions as a group, and each suboption.

Editing Embedded Policies

An embedded policy is embedded for a scope, scope template, client, or client-class (see "Managing IPv6 Addresses" for embedded policies in DHCPv6). To add an embedded policy:


Step 1 In the Web UI, click DHCP, then one of the following: Scopes, Scope Templates, Clients, Client-Classes, Prefixes, or Links.

In the CLI, use the embedded commands such as client-class-policy client-class-name set attribute=value, where the command starts with the object name followed by -policy.

Step 2 In the Web UI, click the name of the object to open its Edit page.

Step 3 In the Web UI, click Edit Embedded Policy under the Embedded Policy section of the page. This action opens the Edit DHCP Embedded Policy page for the object (see Figure 20-3 for a partial view of a client-class embedded policy page).

Figure 20-3 Edit DHCP Embedded Policy Page (Local)

Step 4 In the Web UI, click one of the Modify buttons.

Step 5 After you modify an embedded policy, you return to the editing page for the associated object (Edit Client-Class in the example). You must save the changes to the object that contains the embedded policy by clicking Modify... on the Edit page.


Creating DHCP Option Definition Sets and Option Definitions

In Network Registrar, you configure option values on policies for such things as lease times and router addresses. Numerous RFCs describe the formatting of DHCP option values, beginning with RFC 2132. Option definitions are used in the Web UI and CLI to control formatting of option values in policies. You can define option definitions separately for the DHCPv4 and DHCPv6 address spaces, as:

Standard options—Defined by the RFCs.

Custom options—New or modified option definitions in the supplied dhcp-config or dhcp6-config options definition sets.

Vendor-specific options—Defined in their own option definition sets.

Using Standard Option Definition Sets

Network Registrar provides two standard option definition sets, dhcp-config and dhcp6-config, for DHCPv4 and DHCPv6 option definitions, respectively. These sets are visible in the Web UI when you click DHCP, then Options to open the List DHCP Option Definition Sets page (see Figure 20-4).

Creating an option definition in the standard option definition sets is possible if there is no existing option definition by that name or ID already in the option definition set. The new option definition is identified by an asterisk (*) after its name. You can delete this type of option definition; you cannot delete or overwrite any standard option definition.

Figure 20-4 List DHCP Option Definition Sets Page (Local)

The full list of predefined DHCP option definitions is included in "DHCP Options."


Caution Arbitrarily modifying the standard option definitions (or adding suboption definitions) can adversely affect configurations.

The regular DHCP options definitions are predefined by their own option definition sets in Network Registrar, one for DHCPv4 and one for DHCPv6. To access the regular DHCP options:


Step 1 In the Web UI, click DHCP, then Options to open the List DHCP Option Definition Sets page.

In the CLI:

To view the entire list of standard DHCP option definitions, use option-set dhcp-config list or option-set dhcp6-config list, or option {id nameoption-set show to view a specific option definition. For example:

nrcmd> option-set dhcp-config list 
nrcmd> option subnet-mask dhcp-config show 

To add an option definition to an option definition set, use option id option-set create name type. You cannot add an option definition for an option ID (number) or name that already exists. For example, to add option number 222 with the name example-option in the dhcp-config option set, with a string type, use:

nrcmd> option 222 dhcp-config create example-option AT_STRING 


Note You cannot create suboption definitions by using the CLI. You must use the Web UI.


To get a particular option attribute value, use option optionset get attribute.

To modify an option attribute, use option (id | name} set. You can also unset an option attribute.

Step 2 In the Web UI, click the dhcp-config or dhcp6-config link to open the Edit DHCP Option Definition Set page, then click Add/Edit Option Definitions. View the predefined option definitions on the List DHCP Option Definitions page. These are the options definitions that control the formatting of the option values that you add to policies. If there are suboption definitions, you can expand to show them.

Step 3 In the Web UI, to add an option definition, click Add Option Definition. On the Add DHCP Option Definition page (see Figure 20-5), give the option an ID, name, description, type, and repeat count (whether more than one instance of the option is allowed or required). (For details on the data types and repeat count values, see the "Option Definition Data Types and Repeat Counts" section.)

Figure 20-5 Add DHCP Option Definition Page (Local)


Note You cannot add an option definition for an option number or name that already exists. However, you can modify any option definition that appears as a hyperlink on the page.


Step 4 In the Web UI, click Add Option Definition. Then, on the List DHCP Option Definitions page, click Modify Option Definition Set.


Creating Custom Option Definitions

You can create custom option definitions in the standard option definition sets. Click the dhcp-config or dhcp6-config option definition sets on the List DHCP Option Definition Sets page (see Figure 20-4). Then proceed with Step 3 in the "Using Standard Option Definition Sets" section.

Creating Vendor-Specific Option Definitions

You can send vendor-specific option data to DHCP clients that request them.


Note In prior Network Registrar releases, setting vendor-specific options was available in the CLI by using vendor-option name create, together with setting option data types by using option-datatype name create and option-datatype name defineField. There was only one vendor option code defined, for option 43, and the vendor-option command implicitly operated on this option. As of Network Registrar 6.2, there are several other option codes set aside for vendor-specific options, so that you must explicitly specify the option code number for which you are creating a vendor-specific option definition.


In Network Registrar 6.2, you can create vendor-specific option definitions in the Web UI, or in the CLI by using option id option-set-name create. (For details on the option data types, see the "Option Definition Data Types and Repeat Counts" section.)

Vendor-specific options are sent in the following DHCP options:

vendor-encapsulated-options (43)—Set this to a binary data type, then add the vendor-specific suboption definitions. (The data type of the parent option definition is a placeholder only and it is the suboption definitions that define the valid option value formatting.)

v-i-vendor-info (125), or vendor-options (17) for DHCPv6—Set this to a vendor-opts or vendor-class data type, then add the vendor-specific suboption definitions.

You can create vendor-specific option definitions for DHCPv4 options 43 and 125, and DHCPv6 option 17. You add the vendor-specific option definitions into a vendor option definition set that you create.


Step 1 In the Web UI, click DHCP, then Options to open the List DHCP Option Definition Sets page (see Figure 20-4). View the existing DHCPv4 or DHCPv6 options. Then click Add Option Definition Set to open the Add DHCP Option Definition Set page (see Figure 20-6).

Figure 20-6 Add DHCP Option Definition Set Page (Local)

Step 2 In the Web UI, enter a name for the option definition set, then choose DHCPv4 or DHCPv6 from the DHCP Type drop-down list.

If you are creating vendor-specific option definitions using:

Option 43, do not enter values in the Vendor Option String or Vendor Options Enterprise ID fields.

Option 125 for DHCPv4 or option 17 for DHCPv6, enter a valid Vendor Option String or Enterprise Option ID value. The server ignores any other configured vendor options with an enterprise ID.

In the CLI, option-set dhcp-custom list (or listnames) lists just the vendor-specific option definitions. Use option-set name create dhcp-type to create a DHCP option set. The dhcp-type is either 8-bit (for DHCPv4) or 16-bit (for DHCPv6). For example, to create an option definition set with the name myoptionset for DHCPv4, with an option 125 vendor option string equal to ve-string, enter:

nrcmd> option-set myoptionset create 8-bit vendor-option-string=ve-string 
nrcmd> save 

Step 3 In the Web UI, click Add Option Definition Set.

Step 4 In the Web UI, click the option definition set name.

Step 5 In the Web UI, on the Edit DHCP Option Definition Set page, click Add/Edit Option Definitions. This opens the List DHCP Option Definitions page. Any existing option definitions will appear on this page (custom or vendor-specific option definitions are marked with an asterisk).

In the CLI, use option optionset list to show all the option definitions in a set. To show all the values for the option definitions in the set, use option optionset [show]. Use option optionset get to show individual properties of the option definition. You can also unset an option.

Step 6 In the Web UI, click Add Option Definition. This opens the Add DHCP Option Definition page (see Figure 20-5).

Step 7 In the Web UI, enter the ID number of the option definition, along with its name and a description. The ID must be 43, 125, or 17 (for DHCPv6) for the client to recognize a vendor-specific option definition. The option name does not need to match the one specified in the RFC and can be of your own creation.

Step 8 Choose or enter the data type and repeat count (or enter an absolute repeat count in the next field).

The data type must be:

Binary (AT_BLOB) for option 43.

Vendor-opts (AT_VENDOR_OPTS) for option 125 (for DHCPv4) and option 17 (for DHCPv6).

(For details on the data type and repeat count values, see the "Option Definition Data Types and Repeat Counts" section.)

In the CLI, use option id option-set create name type to create the definition. For example, to create option 43 for the v-s-optionset option set, naming it vendor-opt-43 with a binary data type, use:

nrcmd> option 43 v-s-optionset create vendor-opt-43 
nrcmd> save 

Step 9 In the Web UI, click Add Option Definition. Then, on the List DHCP Option Definitions page, click Modify Option Definition Set.



Caution Changing option properties or deleting the option altogether can have unexpected side effects on policies. If you delete a custom option, also remove it from the policies that include it. Changing an option value in policies changes the way that they are displayed, so you do not need to modify the policy value unless you want the policy to return a differently formatted option value.

Option Definition Data Types and Repeat Counts

The data type values that you can use appear in the following table:

AT_INT8
unsigned 8-bit

AT_SHORT
unsigned 16-bit

AT_INT
unsigned 32-bit

AT_STRING
string

AT_SINT8
signed 8-bit

AT_SSHORT
signed 16-bit

AT_SINT
signed 32-bit

AT_NSTRING
string (no termination)

 

AT_SHRTI
unsigned 16-bit (Intel)

AT_INTI
unsigned 32-bit (Intel)

AT_BLOB
binary

 

AT_SSHRTI
signed 16-bit (Intel)

AT_SINTI
signed 16-bit (Intel)

AT_ZEROSIZE
zero size

AT_DNSNAME
DNS name

AT_IPADDR
IP address

AT_BOOL
boolean

AT_DATE
date

AT-RDNSNAME
relative DNS name

AT_IP6ADDR
IPv6 address

AT_MACADDR
MAC address

AT_TIME
unsigned time

AT_VENDOR-CLASS
vendor-class

AT_VENDOR-OPTS
vendor-opts

AT_TYPECNT
counted-type

AT_STIME
signed time

AT_VENDOR_NOLEN
vendor-nolen

 

AT_RANGEBYTE
bounded byte

AT_RANGESHORT
bounded short


You can view these types in the CLI by using option listtypes.

To set the repeat count in the CLI, set the repeat-count attribute to one of the following, or enter an absolute number:

ZERO_OR_MORE—0+ in the Web UI

ONE_OR_MORE—1+ in the Web UI

EVEN_NUMBER—2n in the Web UI

In the CLI, for example, use:

nrcmd> option 200 ex-opt-def-set set repeat-count=ZERO_OR_MORE 
nrcmd> save 

Adding Suboption Definitions

You can set a suboption definition for the option definition by clicking Add Suboption Definition on the Edit DHCP Option Definition page. This opens the Add DHCP Option Definition page (see Figure 20-5), where you can add the same values as for an option definition. The suboption definition you create is associated with its parent option definition. There can be three levels of suboption definitions.


Note You can add suboption definitions to option definitions by using the Web UI only. You currently cannot do by using the CLI.


Suboption definition formats can be packed or type/length/value (TLV):

Packed—A suboption with a zero ID value and an implicit data type. The option value is the only data in the packet. DHCPv6 options are virtually all defined with packed data. There are no markers for type or length and the layout of the data is inherent in the option definition.

TLV—A suboption with a value of 1 through 255 (or 65535) that includes a type, length, and value. The data in the packet has the type and length preceding the value.

In most cases, you will not be mixing packed with TLV suboptions for the same option.

To enter suboption values when editing policies, see the "Adding Complex Values for Suboptions" section.

Importing and Exporting Option Definition Sets

Importing and exporting option definition sets is a way to copy them between servers. In the CLI, you can import and export option sets by using import option-set file and export option-set name file. For example, to import an option set for Preboot Execution Environment (PXE) clients, modify and import a sample file located in the /examples/dhcp directory:

nrcmd> import option-set /examples/dhcp/OptionSetPXE.txt 

Some of the guidelines for the file format include:

The version string in the file must match the version for the import utility.

The utility imports just the first option definition set found in the file.

Delimit objects using curly brackets ({ }), attributes using parentheses (( )), and lists of objects in attributes using square brackets ([ ]). Delimit string value attributes using quotes (" ").

Using some care, you can also edit the text file to make minor modifications to an option definition set. Network Registrar provides two sample option definition set text files in the examples/dhcp directory, OptionSetJumpStart.txt and OptionSetPXE.txt:

OptionSetJumpStart.txt—Edit the vendor-option-string to match the dhcp-class-identifier (option 60) that your JumpStart clients are sending.

OptionSetPXE.txt—Edit the vendor-option-string to match the dhcp-class-identifier (option 60) that your Pre-boot Execution Environment (PXE) clients are sending.

Setting Option Values for Policies

You enter option values on a policy. The option definitions in your server configuration control the format and values that you enter.

In the Web UI, on the List DHCP Policies page, click a policy to edit it. On the Edit DHCP Policy page:

To enter a standard DHCPv4 option value for a policy, choose it from the DHCPv4 Options drop-down list, then set a value for the option. Click Add Option.

To enter a standard DHCPv6 option value for a policy, choose it from the DHCPv6 Options drop-down list, then set a value for the option. Click Add Option.

To enter a vendor-specific DHCPv6 option value for a policy, choose an option definition set in the DHCPv4 Vendor Options drop-down list and click Select. The page changes to show the drop-down list that includes the option; choose it, then click Add Option.

Click Modify Policy.

In the CLI, use one of these commands:

nrcmd> policy name setOption {name | id} value 
nrcmd> policy name setV6Option {name | id} value 
nrcmd> policy name setVendorOption {name | id} option-set-name value 
nrcmd> policy name setV6VendorOption {name | id} option-set-name value 

To list the options in the policy, use one of these commands:

nrcmd> policy name listOptions 
nrcmd> policy name listV6Options 
nrcmd> policy name listVendorOptions 
nrcmd> policy name lsitV6VendorOptions 

To add suboption values, see the "Adding Complex Values for Suboptions" section.