DHCP Options
DHCP provides a framework for passing configuration information to hosts on a TCP/IP network. Configuration parameters and other control information are carried in tagged data items that are stored in the options field of the DHCP message. The data items themselves are also called options.
This appendix contains DHCP options and BOOTP vendor extensions from RFC 2132, and includes the validation type for each option, as indicated in Table B-10.
This appendix also contains the standard Microsoft client options and several tables displaying the options sorted by categories.
Option Descriptions
The following sections describe the DHCP options in detail:
•RFC 1497 Vendor Extensions
•IP Layer Parameters Per Host
•IP Layer Parameters Per Interface
•Link Layer Parameters Per Interface
•TCP Parameters
•Application and Service Parameters
•DHCPv4 Extension Options
•DHCPv6 Options
•Microsoft Client Options
•Options by Number
•Options by Cisco Prime Network Registrar Name
•Option Validation Types
RFC 1497 Vendor Extensions
Table B-1 lists the vendor extensions as defined in RFC 1497.
Table B-1 RFC 1497 Vendor Extension Options
|
|
|
|
Pad |
0 |
1 octet |
Causes the subsequent fields to align on word boundaries. |
End |
255 |
1 octet |
End of valid information in the vendor field. Subsequent octets should be filled with the Pad options. |
Subnet Mask |
1 |
4 octets |
Client subnet mask, as per RFC 950. If both the Subnet Mask and the Router option are specified in a DHCP reply, the Subnet Mask option must be first. |
Time Offset |
2 |
4 octets |
Offset of the client subnet, in seconds, from Universal Time (UT). The offset is expressed as a twos-complement 32-bit integer. A positive offset indicates a location east of the zero meridian and a negative offset indicates a location west of the zero meridian. |
Router |
3 |
4 octet minimum; multiples of 4 |
List of IP addresses for routers on the client subnet. Routers should be in order of preference. |
Time Server |
4 |
4 octet minimum; multiples of 4 |
List of RFC 868 compliant time servers available to the client. Servers should be in order of preference. |
Name Server Option |
5 |
4 octet minimum; multiples of 4 |
List of IEN 116 name servers available to the client. Servers should be in order of preference. |
Domain Name Server |
6 |
4 octet minimum; multiples of 4 |
List of Domain Name System (STD 13, RFC 1035) name servers available to the client. Servers should be in order of preference. |
Log Server |
7 |
4 octet minimum; multiples of 4 |
List of MIT-LCS UDP log servers available to the client. Servers should be in order of preference. |
Cookie Server |
8 |
4 octet minimum; multiples of 4 |
List of RFC 865-compliant cookie servers available to the client. Servers should be in order of preference. |
LPR Server |
9 |
4 octet minimum; multiples of 4 |
List of RFC 1179-compliant line printer servers available to the client. Servers should be in order of preference. |
Impress Server |
10 |
4 octet minimum; multiples of 4 |
List of Imagen Impress servers available to the client. Servers should be in order of preference. |
Resource Location Server |
11 |
4 octet minimum; multiples of 4 |
List of RFC 887-compliant resource location servers available to the client. Servers should be in order of preference. |
Host Name |
12 |
1 octet minimum |
Name of the client. The name may or may not be qualified with the local domain name. See RFC 1035 for the character set restrictions. |
Boot File Size |
13 |
2 octets |
Number of 512-octet blocks in the default boot file. |
Merit Dump File |
14 |
1 octet minimum |
Path name of a file to which the client core image should be placed in the event the client crashes. The path is formatted as a character string consisting of characters from the NVT ASCII character set. |
Domain Name |
15 |
1 octet minimum |
Domain name that the client should use when resolving hostnames through the Domain Name System. |
Swap Server |
16 |
4 octets |
IP address of the client swap server. |
Root Path |
17 |
1 octet minimum |
Path name that contains the client root disk. The path is formatted as a character string consisting of characters from the NVT ASCII character set. |
Extensions Path |
18 |
1 octet minimum |
Uses a string to specify a file, retrievable through TFTP. The file contains information that can be interpreted in the same way as the 64-octet vendor-extension field within the BOOTP response, with these exceptions: the length of the file is unconstrained, and all references to instances of this option in the file are ignored. |
IP Layer Parameters Per Host
Table B-2 lists the options that affect the operation of the IP layer on a per-host basis.
Table B-2 IP Layer Parameters Per Host Options
|
|
|
|
IP Forwarding Enable/Disable |
19 |
1 octet |
Specifies whether the client should configure its IP layer for packet forwarding. Values: 0=disable; 1=enable |
Non-Local Source Routing Enable/Disable |
20 |
1 octet |
Specifies whether the client should configure its IP layer to allow forwarding of datagrams with non-local source routes. Values: 0=disable; 1=enable |
Policy Filter |
21 |
8 octet minimum; multiples of 8 |
Policy filters for non-local source routing. The filters consist of a list of IP addresses and masks that specify destination/mask pairs with which to filter incoming source routes. Any source-routed datagram whose next-hop address does not match one of the filters should be discarded by the client. |
Maximum Datagram Reassembly Size |
22 |
2 octets |
Maximum size datagram that the client should be prepared to reassemble. Value: 576 minimum |
Default IP Time-to-Live |
23 |
1 octet |
Default TTL that the client should use on outgoing datagrams. Values: 1 to 255 |
Path MTU Aging Timeout |
24 |
4 octets |
Timeout (in seconds) to use when aging Path MTU values (defined in RFC 1191). |
Path MTU Plateau Table |
25 |
2 octets minimum; multiples of 2 |
Table of MTU sizes to use when performing Path MTU Discovery as defined in RFC 1191. The table is formatted as a list of 16-bit unsigned integers, ordered from smallest to largest. Value: 68 minimum |
IP Layer Parameters Per Interface
Table B-3 lists the options that affect the operation of the IP layer on a per-interface basis. A client can issue multiple requests, one per interface, to configure interfaces with their specific parameters.
Table B-3 IP Layer Parameters Per Interface Options
|
|
|
|
Interface MTU |
26 |
2 octets |
Maximum time to live to use on this interface. |
All Subnets Are Local |
27 |
1 octet |
Specifies whether or not the client can assume that all subnets of the IP network to which the client is connected use the same MTU as the subnet of that network to which the client is directly connected. Values: 1=all subnets share same MTU; 0=some directly-connected subnets can have smaller MTUs |
Broadcast Address |
28 |
4 octets |
Broadcast address in use on the client subnet. |
Perform Mask Discovery |
29 |
1 octet |
Specifies whether or not the client should perform subnet mask discovery using ICMP. Values: 0=disable; 1=enable |
Mask Supplier |
30 |
1 octet |
Specifies whether or not the client should respond to subnet mask requests using ICMP. Values: 0=do not respond; 1=respond |
Perform Router Discovery |
31 |
1 octet |
Specifies whether or not the client should solicit routers using the Router Discovery mechanism defined in RFC 1256. Values: 0=disable; 1=enable |
Router Solicitation Address |
32 |
4 octets |
Address to which the client should transmit router solicitation requests. |
Static Route |
33 |
8 octet minimum; multiples of 8 |
List of static routes that the client should install in its routing cache. If multiple routes to the same destination are specified, they are in descending order of priority. The routes consist of a list of IP address pairs. The first address is the destination address, and the second address is the router for the destination. The default route (0.0.0.0) is an illegal destination for a static route. |
Link Layer Parameters Per Interface
Table B-4 lists the options that affect the operation of the data link layer on a per-interface basis.
Table B-4 Link Layer Parameters Per Interface Options
|
|
|
|
Trailer Encapsulation |
34 |
1 octet |
Specifies whether or not the client should negotiate the use of trailers (RFC 893) when using the ARP protocol. Values: 0=do not use; 1=use |
ARP Cache Timeout |
35 |
4 octets |
Timeout in seconds for ARP cache entries. |
Ethernet Encapsulation |
36 |
1 octet |
Specifies whether or not the client should use Ethernet Version 2 (RFC 894) or IEEE 802.3 (RFC 1042) encapsulation if the interface is an Ethernet. Value: 0=use RFC 894 encapsulation; 1=use RFC 1042 encapsulation |
TCP Parameters
Table B-5 lists the options that affect the operation of the TCP layer on a per-interface basis.
Table B-5 TCP Parameter Options
|
|
|
|
TCP Default TTL |
37 |
1 octet |
Default TTL that the client should use when sending TCP segments. Value: minimum 1 |
TCP Keepalive Interval |
38 |
4 octets |
Interval (in seconds) that the client TCP should wait before sending a keepalive message on a TCP connection. The time is specified as a 32-bit unsigned integer. A value of zero indicates that the client should not generate keepalive messages on connections unless specifically requested by an application. Value: 32-bit unsigned; 0=do not generate keepalive messages unless specifically requested. |
TCP Keepalive Garbage |
39 |
1 octet |
Specifies the whether or not the client should send TCP keep-alive messages with an octet of garbage for compatibility with older implementations. Values: 0=do not send; 1=send |
Application and Service Parameters
Table B-6 lists some miscellaneous options used to configure miscellaneous applications and services.
Table B-6 Application and Service Parameter Options
|
|
|
|
Network Information Service (NIS) Domain |
40 |
1 octet minimum |
Name of the client NIS domain. The domain is formatted as a character string consisting of characters from the NVT ASCII character set. |
Network Information Service (NIS) Servers |
41 |
4 octet minimum; multiples of 4 |
List of IP addresses indicating NIS servers available to the client. Servers should be in order of preference. |
Network Time Protocol Servers |
42 |
4 octet minimum; multiples of 4 |
List of IP addresses indicating NTP servers that are available to the client. Servers should be in order of preference. |
Vendor-Specific Information |
43 |
1 octet minimum |
This option is used by clients and servers to exchange vendor-specific information. The information is an opaque object of n octets, presumably interpreted by vendor-specific code on the clients and servers. The definition of this information is vendor specific. The vendor is indicated in the dhcp-class-identifier option. Servers not equipped to interpret the vendor-specific information sent by a client must ignore it (although it can be reported). Clients that do not receive desired vendor-specific information should make an attempt to operate without it, although they can do so (and announce they are doing so) in a degraded mode. If a vendor potentially encodes more than one item of information in this option, then the vendor should encode the option using encapsulated vendor-specific options as described here. The encapsulated vendor-specific options field should be encoded as a sequence of code, length, and value fields of identical syntax to the DHCP options field with these exceptions: •There should not be a magic cookie field in the encapsulated vendor-specific extensions field. •Codes other than 0 or 255 can be redefined by the vendor within the encapsulated vendor-specific extensions field, but should conform to the tag-length-value syntax defined in section 2. Code 255 (END), if present, signifies the end of the encapsulated vendor extensions, not the end of the vendor extensions field. If the code 255 is not present, then the end of the enclosing vendor-specific information field is taken as the end of the encapsulated vendor-specific extensions field. |
NetBIOS over TCP/IP Name Server |
44 |
4 octet minimum; multiples of 4 |
List of RFC 1001/1002 NBNS name servers in order of preference. |
NetBIOS over TCP/IP Datagram Distribution Server |
45 |
4 octet minimum; multiples of 4 |
List of RFC 1001/1002 NBDD servers in order of preference. |
NetBIOS over TCP/IP Node Type |
46 |
1 octet |
Allows NetBIOS over TCP/IP client, which are configured as described in RFC 1001/1002. Values: Single hexadecimal octet that identifies the client type: •0x1=B-node (broadcast node) •0x2=P-node (point-to-point node) •0x4=M-node (mixed node) •0x8=H-node |
NetBIOS over TCP/IP Scope |
47 |
1 octet minimum |
NetBIOS over TCP/IP scope parameter for the client as specified in RFC 1001/1002. |
X Window System Font Server |
48 |
4 octet minimum; multiples of 4 |
List of X Window System Font servers available to the client. Servers should be in order of preference. |
X Window System Display Manager |
49 |
4 octet minimum; multiples of 4 |
List of IP addresses of systems that are running the X Window System Display Manager and are available to the client. Addresses should be in order of preference. |
Network Information Service (NIS+) Domain |
64 |
1 octet minimum |
Name of the client NIS+ domain. The domain is formatted as a character string consisting of characters from the NVT ASCII character set. |
Network Information Service (NIS+) Servers |
65 |
4 octet minimum; multiples of 4 |
List of IP addresses indicating NIS+ servers available to the client. Servers should be in order of preference. |
Mobile IP Home Agent |
68 |
0 octets minimum; multiples of 4; expected, 4 octets (single home agent address) |
List of IP addresses indicating mobile IP home agents available to the client. Agents should be in order of preference. Value: 32-bit address; 0=no home agents available |
Simple Mail Transport Protocol (SMTP) Server |
69 |
4 octet minimum; multiples of 4 |
List of SMTP servers available to the client. Servers should be in order of preference. |
Post Office Protocol (POP3) Server |
70 |
4 octet minimum; multiples of 4 |
List of POP3 servers available to the client. Servers should be in order of preference. |
Network News Transport Protocol (NNTP) Server |
71 |
4 octet minimum; multiples of 4 |
List of NNTP servers available to the client. Servers should be in order of preference. |
World Wide Web (WWW) Server |
72 |
4 octet minimum; multiples of 4 |
List of World Wide Web (WWW) servers available to the client. Servers should be in order of preference. |
Finger Server |
73 |
4 octet minimum; multiples of 4 |
List of Finger servers available to the client. Servers should be in order of preference. |
Internet Relay Chat Server |
74 |
4 octet minimum; multiples of 4 |
List of IRC servers available to the client. Servers should be in order of preference. |
StreetTalk Server |
75 |
4 octet minimum; multiples of 4 |
List of StreetTalk servers available to the client. Servers should be in order of preference. |
StreetTalk Directory Assistance (STDA) Server |
76 |
4 octet minimum; multiples of 4 |
List of STDA servers available to the client. Servers should be in order of preference. |
DHCPv4 Extension Options
Table B-7 lists the DHCPv4 extension options.
Table B-7 DHCPv4 Extensions
|
|
|
|
Requested IP Address |
50 |
4 octets |
Used in a client request (DHCPDISCOVER) to allow the client to request that a particular IP address be assigned. |
IP Address Lease Time |
51 |
4 octets |
Used in a client request (DHCPDISCOVER or DHCPREQUEST) to allow the client to request a lease time for the IP address. In a server reply (DHCPOFFER), a DHCP server uses this option to specify the lease time it is willing to offer. Value: seconds, as 32-bit unsigned integer |
Option Overload |
52 |
1 octet |
Indicates that the DHCP sname or file fields are being overloaded by using them to carry DHCP options. A DHCP server inserts this option if the returned parameters will exceed the usual space allotted for options. If this option is present, the client interprets the specified additional fields after it concludes interpretation of the standard option fields. Values: 1=file field is used to hold options; 2=sname field is used to hold options; 3=both fields are used to hold options |
DHCP Message Type |
53 |
1 octet |
Used to convey the type of DHCP message. The preset value is 1 (DHCPDISCOVER). Values: 1=DHCPDISCOVER; 2=DHCPOFFER; 3=DHCPREQUEST; 4=DHCPDECLINE; 5=DHCPACK; 6=DHCPNAK; 7=DHCPRELEASE; 8=DHCPINFORM; 13=LEASEQUERY |
Server Identifier |
54 |
4 octets |
Used in DHCPOFFER and DHCPREQUEST messages, and can optionally be included in the DHCPACK and DHCPNAK messages. DHCP servers include this option in the DHCPOFFER in order to allow the client to distinguish between lease offers. DHCP clients use the contents of the server identifier field as the destination address for any DHCP messages unicast to the DHCP server. DHCP clients also indicate which of several lease offers is being accepted by including this option in a DHCPREQUEST message. The identifier is the IP address of the selected server. |
Parameter Request List |
55 |
1 octet minimum |
Used by a DHCP client to request values for specified configuration parameters. The list of requested parameters is specified as n octets, where each octet is a valid DHCP option code as defined in this document. The client can list the options in order of preference. The DHCP server does not have to return the options in the requested order, but must try to insert the options in the order that the client requested. |
Message |
56 |
1 octet minimum |
Used by a DHCP server to provide an error message to a DHCP client in a DHCPNAK message in the event of a failure. A client can use this option in a DHCPDECLINE message to indicate why the client declined the offered parameters. The message consists of n octets of NVT ASCII text, which the client can display on an available output device. |
Maximum DHCP Message Size |
57 |
2 octets |
Maximum-length DHCP message that a server is willing to accept. The length is specified as an unsigned 16-bit integer. A client can use the maximum DHCP message size option in DHCPDISCOVER or DHCPREQUEST messages, but should not use the option in DHCPDECLINE messages. Value: 576 minimum |
Renewal (T1) Time Value |
58 |
4 octets |
Time interval from address assignment until the client transitions to RENEWING state. Value: seconds, as 32-bit unsigned integer |
Rebinding (T2) Time Value |
59 |
4 octets |
Time interval from address assignment until the client transitions to REBINDING state. Value: seconds, as 32-bit unsigned integer |
Vendor Class Identifier |
60 |
1 octet minimum |
Used by DHCP clients to optionally identify the vendor type and configuration of a DHCP client. The information is a string of n octets, interpreted by servers. Vendors can choose to define specific vendor class identifiers to convey particular configuration or other identification information about a client. For example, the identifier can encode the client hardware configuration. Servers not equipped to interpret the class-specific information sent by a client must ignore it (although it can be reported). Servers that respond should only use option 43 to return the vendor-specific information to the client. |
Client-Identifier |
61 |
2 octet minimum |
Used by DHCP clients to specify their unique identifier. DHCP servers use this value to index their database of address bindings. This value is expected to be unique for all clients in an administrative domain. DHCP servers should treat identifiers as opaque objects. The client identifier can consist of type-value pairs similar to the htype/chaddr fields. For instance, it can consist of a hardware type and hardware address. In this case, the type field should be one of the ARP hardware types defined in STD2. A hardware type of 0 (zero) should be used when the value field contains an identifier other than a hardware address (for example, a fully qualified domain name). For correct identification of clients, each client-identifier must be unique among the client-identifiers used on the subnet to which the client is attached. Vendors and system administrators are responsible for choosing client-identifiers that meet this requirement for uniqueness. |
TFTP Server Name |
66 |
1 octet minimum |
Identifies a TFTP server when the sname field in the DHCP header has been used for DHCP options. |
Bootfile Name |
67 |
1 octet minimum |
Identifies a bootfile when the file field is the DHCP header that has been used for DHCP options. |
Relay Agent Information |
82 |
|
Identifies the DHCP relay agent information. |
iSNS |
83 |
14 bytes minimum |
Identifies the Internet Storage Name Service (see RFC 4174) |
BCMS Controller Domain |
88 |
Variable |
List of Broadcast and Multicast Service (BCMS) controller domains (see RFC 4280) |
BCMS Address |
89 |
4 octets minimum |
List of IP addresses for the BCMS controller (see RFC 4280) |
Lease Query Client Last Transaction Time |
91 |
4 octets |
Time of the most recent access of the client sending a DHCPLEASEQUERY (see RFC 4388). |
Lease Query Associated IP Addresses |
92 |
4 octets minimum |
All IP addresses associated with the client specified in a particular DHCPLEASEQUERY message (see RFC 4388). |
Microsoft Client Options
Table B-8 lists the standard Microsoft client options.
Table B-8 Microsoft DHCP Client Options
|
|
|
dhcp-lease-time |
51 |
14 days |
domain-name |
15 |
A domain name such as cisco.com |
domain-name-servers |
6 |
IP address of the name servers |
netbios-name-servers |
44 |
WINS server address |
netbios-node-type |
46 |
Identifies the NetBIOS client type; note that Cisco Prime Network Registrar displays a warning if it is not present |
routers |
3 |
IP address of the router for this subnet |
DHCPv6 Options
Table B-9 lists the DHCPv6 options, along with their defined data types. All the option packets include at least an option length (option-len) and a variable length data field. There can also be additional parameter settings, as described in the table. Mod in the Description column indicates that the option definition is modifiable. Many of these options are described in RFC 3315.
Table B-9 DHCPv6 Options
Cisco Prime Network Registrar Name
(Type)
|
|
Description (Mod=modifiable)
|
client-identifier AT_BLOB |
1 |
DUID identifying a client between a client and a server. |
server-identifier AT_BLOB |
2 |
DUID identifying a server between a client and a server. |
ia-na AT_BLOB |
3 |
Nontemporary Addresses option with the associated parameters and addresses. Parameters are the unique ID, time the client contacts the addresses in the IA to extend the lifetime, and time the client contacts any available server to extend the lifetime of the addresses. |
ia-ta AT_BLOB |
4 |
Temporary Addresses option with the associated parameters and addresses. |
iaaddr AT_BLOB |
5 |
IPv6 addresses associated with an IA_NA or IA_TA. (The IAADRR must be encapsulated in the options field of an IA_NA or IA_TA option.) The IAADDR option includes preferred and valid lifetime fields, and the options field that encapsulates the options specific to this address. |
oro AT_SHORT |
6 |
Option Request option (ORO) that identifies a list of options in a message between a client and a server. A client can include this option in a Solicit, Request, Renew, Rebind, Confirm, or Information-request message to inform the server about options the client wants from the server. A server can include this option in a Reconfigure message to indicate which option updates the client should request. |
preference AT_INT8 |
7 |
A server sends this option to a client to affect what server the client selects (Mod). |
elapsed-time AT_SHORT |
8 |
A client sends this option to a server to indicate how long the client has been trying to complete a message exchange (Mod). |
relay-message AT_BLOB |
9 |
DHCP message in a Relay-forward or Relay-reply message. |
auth AT_BLOB |
11 |
Authenticates the identity and contents of a DHCP message. The parameters are the authentication protocol, the authentication algorithm, the replay detection method (RDM), and the authentication information. |
server-unicast AT_IP6ADDR |
12 |
The server sends this option to a client to indicate that the client can unicast messages to the server. |
status-code AT_BLOB |
13 |
Returns a status indication related to the DHCP message or option in which it appears. The parameters are the status code and status message. |
rapid-commit AT_ZEROSIZE |
14 |
Signals use of the two-message exchange for address assignment. |
user-class AT_TYPECNT |
15 |
Clients use this option to identify the type or category of user or applications it represents. A zero type count value field followed by user data (as a blob). |
vendor-class AT_VENDOR_CLASS |
16 |
Clients use this option to identify the vendor that manufactured the hardware on which they are running. |
vendor-opts AT_VENDOR_OPTS |
17 |
Clients and servers use this option to exchange vendor-specific information. The enterprise ID for the CableLabs vendor is 4491; the suboptions for CableLabs are listed in Table C-4. |
interface-id AT_BLOB |
18 |
Relay agents use this option to identify the interface on which the client message is received. |
reconfigure-message AT_INT8 |
19 |
The server includes this in a Reconfigure message to indicate whether the client should respond with a Renew or Information-request message. |
reconfigure-accept AT_ZEROSIZE |
20 |
Clients use this option to announce to the server whether the client is willing to accept Reconfigure messages. |
sip-servers-name AT_DNSNAME |
21 |
Domain names of the SIP outbound proxy servers for the client (Mod). See RFC 3319. |
sip-servers-address AT_IP6ADDR |
22 |
IPv6 addresses of the SIP outbound proxy servers for the client (Mod). |
dns-servers AT_IP6ADDR |
23 |
IPv6 addresses of DNS recursive name servers (Mod). |
domain-list AT_DNSNAME |
24 |
Domain names in the domain search list (Mod). |
ia-pd AT_BLOB |
25 |
IPv6 prefix delegation identity association and its associated parameters and prefixes. Parameters are the unique ID, time the client contacts the addresses in the IA to extend the lifetime, and time the client contacts any available server to extend the lifetime of the addresses. |
iaprefix AT_BLOB |
26 |
IPv6 prefixes associated with an IA_PD. The prefix must be encapsulated in the options field of an IA_PD option. Parameters are the valid and preferred lifetimes, prefix length, and the prefix. |
nis-servers AT_IP6ADDR |
27 |
List of IPv6 addresses of Network Information Service (NIS) servers available to the client (see RFC 3898) (Mod). |
nisp-servers AT_IP6ADDR |
28 |
List of IPv6 addresses of NIS+ servers available to the client (Mod). |
nis-domain-name AT_DNSNAME |
29 |
Conveys the NIS domain name to the client (Mod). |
nisp-domain-name AT_DNSNAME |
30 |
Conveys the NIS+ domain name to the client (Mod). |
sntp-servers AT_IP6ADDR |
31 |
List of Simple Network Time Protocol (SNTP) servers available to the client (see RFC 4075) (Mod). |
info-refresh-time AT_TIME |
32 |
Sets an upper bound for how long a client should wait before refreshing DHCPv6 information (see RFC 4242) (Mod). |
bcms-server-d AT_DNSNAME |
33 |
List of BCMS controller domains (see RFC 4280) (Mod). |
bcms-server-a AT_IP6ADDR |
34 |
List of IPv6 addresses for the Broadcast and Multicast Service (BCMS) controller (see RFC 4280) (Mod). |
geoconf-civic AT_BLOB |
36 |
DHCP civic addresses configuration (Mod). |
remote-id AT_BLOB |
37 |
Relay agents that terminate switched or permanent circuits can add this option to identify remote hosts (see RFC 4649) (Mod). |
relay-agent-subscriber-id AT_BLOB |
38 |
Allows assignment and activation of subscriber-specific actions (see RFC 4580) (Mod). |
client-fqdn AT_BLOB |
39 |
DHCP client FQDN (Mod). |
new-posix-timezone AT_BLOB |
41 |
POSIX time zone, for example, EST5EDT4, M3.2.0/02:00,M11.1.0/02:00. |
new-tzdb-timezone AT_BLOB |
42 |
POSIX time zone database name, for example, Europe/Zurich. |
ero AT_BLOB |
43 |
Relay agent Echo Request option to inform the server of the list of relay agent options to echo back. |
lq-query AT_BLOB |
44 |
Used only in a LEASEQUERY message; identifies the query being performed. The option includes the query type, link-address (or 0::0), and options to provide data needed for the query. |
client-data AT_BLOB |
45 |
Encapsulates the data for a single client on a single link in a LEASEQUERY-REPLY message. |
clt-time AT_TIME |
46 |
Client last transaction time encapsulated in the client-data option; identifies how long ago the server last communicated with the client (in seconds). |
lq-relay-data AT_BLOB |
47 |
Used only in a LEASEQUERY-REPLY message; provides the relay agent data used when the client last communicated with the server. |
lq-client-link AT_IP6ADDR |
48 |
Used only in a LEASEQUERY-REPLY message; identifies the links on which the client has one or more bindings. It is used in reply to a query when no link-address was specified and the client is found to be on more than one link. |
lost-server AT_DNSNAME |
51 |
A DHCPv6 client will request a LoST server domain name in an Options Request Option (ORO) (see RFC 3315) (Mod). This option contains a single domain name and must contain precisely one root label. |
capwap_ac_v6 AT_STRING |
52 |
Carries a list of 128-bit (binary) IPv6 addresses indicating one or more Control and Provisioning of Wireless Access Point (CAPWAP) Access Controllers (ACs) available to the Wireless Termination Point (WTP) (see RFC 5417). |
mos-address AT_IP6ADDR |
54 |
Mobility Sever (MoS) IPv6 Address for DHCP v4. |
mos-fqdn AT_BLOB |
55 |
Mobility Sever (MoS) Domain Name List for DHCPv6. |
ntp-server AT_BLOB |
56 |
Serves as a container for server location information related to one Network Time Protocol (NTP) server or Simple Network Time Protocol (SNTP) server. This option can appear multiple times in a DHCPv6 message. Each instance of this option is to be considered by the NTP client or SNTP client as a server to include in its configuration. The option itself does not contain any value. Instead, it contains one or several suboptions that carry NTP server or SNTP server location. |
access-domain AT_DNSNAME |
57 |
Defines the domain name associated with the access network. This option contains a single domain name and, as such, must contain precisely one root label. |
sip-ua-cs-domains AT_DNSNAME |
58 |
Defines the list of domain names in the Session Initiation Protocol (SIP) User Agent Configuration Service Domains. |
bootfile-url AT_NSTRING |
59 |
Informs the client about a URL to a boot file. |
bootfile-param AT_TYPECNT |
60 |
Sent by the server to the client. It consists of multiple UTF-8 (see RFC3629) strings for specifying parameters for the boot file. |
client-arch-type AT_SHORT |
61 |
Provides parity with the Client System Architecture Type option (option 93) defined for DHCPv4. |
nii AT_BLOB |
62 |
Provides parity with the Client Network Interface Identifier option (option 94) defined for DHCPv4. |
geoloc AT_BLOB |
63 |
Specifies the coordinate-based geographic location of the client, to be provided by the server. |
aftr-name AT_DNSNAME |
64 |
Defines a fully qualified domain name of the AFTR tunnel endpoint. |
erp-local-domain-name AT_DNSNAME |
65 |
Contains the name of the local ERP domain. |
Option Tables
The following tables display the DHCP options in various ways. They show the options sorted numerically, by Cisco Prime Network Registrar name, and by category.
DHCP options have a prescribed format and allowed values for their option parameters. Table B-10 lists each DHCP option and parameter type (in the Validation column). The parameter formats and allowed values come from the DHCP and Internet RFCs. All the DHCP options appear, but clients control only some, and the CLI only others.
Options by Number
Table B-10 shows the DHCPv4 options sorted by option number, and includes the validation type. (See Table B-12 for details on the option validation types found in the Validation column.) A 0+ in the Comments column means a repeat count of zero or more occurrences, 1+ means one or more occurrences, 2n means multiple occurrences in multiples of 2. Comments also indicate whether the option includes suboptions, and, if so, how many, and whether the option is nonmodifiable (NM).
Tip For the syntax for adding more complex option data values for suboptions, see the "Adding Complex Values for Suboptions" section.
Table B-10 DHCPv4 Options by Number
|
Cisco Prime Network Registrar Name
|
|
|
|
0 |
pad |
Pad |
AT_NOLEN |
NM |
1 |
subnet-mask |
Subnet Mask |
AT_IPADDR |
|
2 |
time-offset |
Time Offset |
AT_STIME |
Replaced by tz- options (RFC 4833) |
3 |
routers |
Router |
AT_IPADDR |
1+ |
4 |
time-servers |
Time Server |
AT_IPADDR |
1+ |
5 |
name-servers |
Name Server |
AT_IPADDR |
1+ |
6 |
domain-name-servers |
Domain Server |
AT_IPADDR |
1+ |
7 |
log-servers |
Log Server |
AT_IPADDR |
1+ |
8 |
cookie-servers |
Quotes Server |
AT_IPADDR |
1+ |
9 |
lpr-servers |
LPR Server |
AT_IPADDR |
1+ |
10 |
impress-servers |
Impress Server |
AT_IPADDR |
1+ |
11 |
resource-location-servers |
RLP Server |
AT_IPADDR |
1+ |
12 |
host-name |
Host Name |
AT_NSTRING |
|
13 |
boot-size |
Boot File Size |
AT_SHORT |
|
14 |
merit-dump |
Merit Dump File |
AT_NSTRING |
|
15 |
domain-name |
Domain Name |
AT_NSTRING |
|
16 |
swap-server |
Swap Server |
AT_IPADDR |
|
17 |
root-path |
Root Path |
AT_NSTRING |
|
18 |
extensions-path |
Extension File |
AT_NSTRING |
|
19 |
ip-forwarding |
Forward On/Off |
AT_BOOL |
|
20 |
non-local-source-routing |
SrcRte On/Off |
AT_BOOL |
|
21 |
policy-filters |
Policy Filter |
AT_IPADDR |
2n |
22 |
max-dgram-reassembly |
Maximum DG Assembly |
AT_SHORT |
|
23 |
Default-ip-ttl |
Default IP TTL |
AT_RANGEBYTE |
|
24 |
path-mtu-aging-timeout |
MTU Timeout |
AT_TIME |
|
25 |
path-mtu-plateau-tables |
MTU Plateau |
AT_RANGESHORT |
2n |
26 |
interface-mtu |
MTU Interface |
AT_RANGESHORT |
|
27 |
all-subnets-local |
MTU Subnet |
AT_BOOL |
|
28 |
broadcast-address |
Broadcast Address |
AT_IPADDR |
|
29 |
perform-mask-discovery |
Mask Discovery |
AT_BOOL |
|
30 |
mask-supplier |
Mask Supplier |
AT_BOOL |
|
31 |
router-discovery |
Router Discovery |
AT_BOOL |
|
32 |
router-solicitation-address |
Router Request |
AT_IPADDR |
|
33 |
static-routes |
Static Route |
AT_IPADDR |
2n |
34 |
trailer-encapsulation |
Trailers |
AT_BOOL |
|
35 |
arp-cache-timeout |
ARP Timeout |
AT_TIME |
|
36 |
ieee802.3-encapsulation |
Ethernet |
AT_BOOL |
|
37 |
default-tcp-ttl |
Default TCP TTL |
AT_RANGEBYTE |
|
38 |
tcp-keepalive-interval |
Keepalive Time |
AT_TIME |
|
39 |
tcp-keepalive-garbage |
Keepalive Data |
AT_BOOL |
|
40 |
nis-domain |
NIS Domain |
AT_STRING |
|
41 |
nis-servers |
NIS Servers |
AT_IPADDR |
1+ |
42 |
ntp-servers |
NTP Servers |
AT_IPADDR |
1+ |
43 |
vendor-encapsulated- options |
Vendor Specific |
AT_BLOB |
NM |
44 |
netbios-name-servers |
NetBIOS Name Server |
AT_IPADDR |
1+ |
45 |
netbios-dd-servers |
NetBIOS Distribution Server |
AT_IPADDR |
1+ |
46 |
netbios-node-type |
NetBIOS Node Type |
AT_RANGEBYTE |
|
47 |
netbios-scope |
NetBIOS Scope |
AT_NSTRING |
|
48 |
font-servers |
X Window Font |
AT_IPADDR |
1+ |
49 |
x-display-managers |
X Window Manager |
AT_IPADDR |
1+ |
50 |
dhcp-requested-address |
Address Request |
AT_IPADDR |
|
51 |
dhcp-lease-time |
Address Time |
AT_TIME |
NM |
52 |
dhcp-option-overload |
Overload |
AT_OVERLOAD |
|
53 |
dhcp-message-type |
DHCP Message Type |
AT_MESSAGE |
NM (See the DHCP Message Type option in Table B-7) |
54 |
dhcp-server-identifier |
DHCP Server ID |
AT_IPADDR |
|
55 |
dhcp-parameter-request- list |
Parameter List |
AT_INT8 |
0+ |
56 |
dhcp-message |
DHCP Message |
AT_NSTRING |
NM |
57 |
dhcp-max-message-size |
DHCP Maximum Message Size |
AT_SHORT |
NM |
58 |
dhcp-renewal-time |
Renewing Time |
AT_TIME |
NM |
59 |
dhcp-rebinding-time |
Rebinding Time |
AT_TIME |
NM |
60 |
dhcp-class-identifier |
Class Identifier |
AT_NSTRING |
|
61 |
dhcp-client-identifier |
Client Identifier |
AT_BLOB |
|
62 |
netwareip-domain |
NetWare/IP Domain |
AT_NSTRING |
|
63 |
netwareip-information |
NetWare/IP Option |
AT_BLOB |
|
64 |
nis+-domain |
NIS Domain Name |
AT_NSTRING |
|
65 |
nis+-servers |
NIS Server Address |
AT_IPADDR |
1+ |
66 |
tftp-server |
TFTP Server Name |
AT_NSTRING |
|
67 |
boot-file |
Bootfile Name |
AT_NSTRING |
|
68 |
mobile-ip-home-agents |
Mobile IP Home Agent |
AT_IPADDR |
0+ |
69 |
smtp-servers |
SMTP Server |
AT_IPADDR |
1+ |
70 |
pop3-servers |
POP3 Server |
AT_IPADDR |
1+ |
71 |
nntp-servers |
NNTP Server |
AT_IPADDR |
1+ |
72 |
www-servers |
WWW Server |
AT_IPADDR |
1+ |
73 |
finger-servers |
Finger Server |
AT_IPADDR |
1+ |
74 |
irc-servers |
IRC Server |
AT_IPADDR |
1+ |
75 |
streettalk-servers |
StreetTalk Server |
AT_IPADDR |
1+ |
76 |
streettalk-directory- assistance-servers |
STDA Server |
AT_IPADDR |
1+ |
77 |
dhcp-user-class-id |
User Class ID |
AT_TYPECNT |
Suboptions (2) |
78 |
slp-directory-agent |
Service Location Protocol Directory Agent |
AT_BLOB |
Suboptions (2) |
79 |
slp-service-scope |
SLP Service Scope |
AT_BLOB |
Suboptions (2) |
80 |
rapid-commit |
Rapid Commit |
AT_ZEROSIZE |
|
81 |
client-fqdn |
Client FQDN |
AT_BLOB |
Suboptions (4) |
82 |
relay-agent-info |
Relay Agent Information |
AT_BLOB |
For suboptions, see Table C-3 |
83 |
iSNS |
Internet Storage Name Service (RFC4174) |
AT_BLOB |
Suboptions (7) |
85 |
nds-servers |
NDS Servers |
AT_IPADDR |
1+ |
86 |
nds-tree |
NDS Tree Name |
AT_NSTRING |
|
87 |
nds-context |
NDS Context |
AT_NSTRING |
|
88 |
bcms-servers-d |
BCMS Controller Domain (RFC 4280) |
AT_DNSNAME |
1+ |
89 |
bcms-servers-a |
BCMS Address |
AT_IPADDR |
1+ |
90 |
authentication |
Authentication |
AT_BLOB |
Suboptions (5) |
91 |
client-last-transaction- time |
Lease Query Client Last Transaction Time |
AT_TIME |
|
92 |
associated-ip |
Lease Query Associated IP Addresses |
AT_IPADDR |
1+ |
93 |
pxe-client-arch |
|
AT_SHORT |
|
94 |
pxe-client-network-id |
|
AT_BLOB |
Suboptions (2) |
95 |
ldap-url |
|
AT_NSTRING |
|
97 |
pxe-client-machine-id |
|
AT_BLOB |
Suboptions (2) |
98 |
user-auth |
|
AT_NSTRING |
|
99 |
geoconf-civic |
Civic Addresses Configuration |
AT_BLOB |
|
100 |
tz-posix |
IEEE 1003.1 String |
AT_NSTRING |
|
101 |
tz-database |
Time Zone Database |
AT_NSTRING |
|
112 |
netinfo-parent-server-addr |
|
AT_IPADDR |
|
113 |
netinfo-parent-server-tag |
|
AT_NSTRING |
|
114 |
initial-url |
|
AT_NSTRING |
|
116 |
auto-configure |
Autoconfiguration |
AT_RANGEBYTE |
|
117 |
name-service-search |
Name Service Search |
AT_SHORT |
1+ |
118 |
subnet-selection |
Subnet Selection |
AT_IPADDR |
|
119 |
domain-search |
Domain Search |
AT_BLOB |
|
120 |
sip-servers |
SIP Servers |
AT_BLOB |
Suboptions (2) |
121 |
classless-static-route |
Classless Static Route |
AT_BLOB |
|
122 |
cablelabs-client- configuration) |
CableLabs Client Configuration |
AT_BLOB |
Suboptions (10) (see the "cablelabs-client- configuration" section) |
123 |
geo-conf |
GeoConf Option |
AT_BLOB |
|
124 |
v-i-vendor-class |
Vendor-Identifying Vendor Class |
AT_VENDOR_CLASS |
NM |
125 |
v-i-vendor-info |
Vendor-Identifying Vendor-Specific Info |
AT_VENDOR_OPTS |
See also the cablelabs-125 suboptions in Table C-3 |
128 |
mcns-security-server |
-- |
AT_IPADDR |
|
138 |
capwap-ac-v4 |
|
AT_IPADDR |
1+ |
139 |
mos-address |
|
AT_BLOB |
0+ |
140 |
mos-fqdn |
|
AT_BLOB |
0+ |
141 |
sip-ua-cs-domains |
|
AT_DNSNAME |
0+ |
142 |
andsf-v4 |
Access Network Discovery and Selection Function |
AT_IPADDR |
|
143 |
andsf-v6 |
Access Network Discovery and Selection Function |
AT_IP6ADDR |
|
144 |
geoloc |
Geospatial Location with Uncertainty |
AT_BLOB |
|
150 |
tftp-server-address |
TFTP |
AT_IPADDR |
1+ |
161 |
cisco-leased-ip |
Cisco |
AT_IPADDR |
|
162 |
cisco-client-requested- host-name |
Cisco |
AT_NSTRING |
|
163 |
cisco-client-last- transaction-time |
Cisco |
AT_INT |
|
185 |
vpn-id |
VPN Identifier |
AT_BLOB |
NM: Suboptions (2) |
209 |
pxelinux-config-file |
|
AT_NSTRING |
|
210 |
pxelinux-path-prefix |
|
AT_NSTRING |
|
211 |
prelinux-reboot-time |
|
AT_TIME |
|
212 |
6rd |
|
AT_BLOB |
|
213 |
access-domain |
|
AT_DNSNAME |
|
220 |
subnet-alloc |
Subnet Allocation |
AT_BLOB |
Suboptions (5) |
221 |
cisco-vpn-id |
Cisco VPN Identifier |
AT_BLOB |
Suboptions (2) |
251 |
cisco-auto-configure |
Cisco Autoconfiguration |
AT_RANGEBYTE |
|
255 |
end |
End |
AT_NOLEN |
NM |
Options by Cisco Prime Network Registrar Name
Table B-11 lists the DHCP options by Cisco Prime Network Registrar name. (For each option validation type, cross-reference it by number to Table B-10 and check the Validation column.)
Table B-11 DHCP Options by Cisco Prime Network Registrar Name
Cisco Prime Network Registrar Name
|
|
|
|
access-domain |
213 |
Access Network Domain Name |
DHCPv4 |
access-domain |
57 |
Access Network Domain Name |
DHCPv6 |
aftr-name |
64 |
AFTR tunnel endpoint domain name |
DHCPv6 |
all-subnets-local |
27 |
All Subnets Are Local |
Interface |
arp-cache-timeout |
35 |
ARP Cache Timeout |
Interface |
associated-ip |
92 |
Lease Query Associated IP |
DHCPv4 |
auth |
11 |
Authentication |
DHCPv6 |
authentication |
90 |
Authentication |
-- |
auto-configuration |
116 |
Auto-Configuration |
DHCPv4 |
bcms-server-a |
34 |
BCMS Address v6 |
DHCPv6 |
bcms-servers-a |
89 |
BCMS Address |
DHCPv4 |
bcms-server-d |
33 |
BCMS Controller Domain v6 |
DHCPv6 |
bcms-servers-d |
88 |
BCMS Controller Domain |
DHCPv4 |
bootfile-url |
59 |
Boot File Uniform Resource Locator (URL) |
DHCPv6 |
bootfile-param |
60 |
Boot File Parameters |
DHCPv6 |
boot-file |
67 |
Bootfile Name |
BOOTP |
boot-size |
13 |
Boot File Size |
BOOTP |
broadcast-address |
28 |
Broadcast Address |
Interface |
cablelabs-client-configuration |
122 |
CableLabs Client Configuration |
Interface |
capwap_ac_v4 |
138 |
CAPWAP AC |
DHCPv4 |
capwap_ac_v6 |
52 |
CAPWAP AC |
DHCPv6 |
cisco-autoconfigure |
251 |
Cisco Autoconfiguration |
DHCPv4 |
cisco-client-last-transaction-time |
163 |
Cisco Client Last Transaction Time |
DHCPv4 |
cisco-client-requested-host-name |
162 |
Cisco Client Requested Host Name |
DHCPv4 |
cisco-leased-ip |
161 |
Cisco Leased IP Address |
DHCPv4 |
cisco-vpn-id |
221 |
Cisco VPN Identifier |
DHCPv4 |
classless-static-route |
121 |
Classless Static Route |
DHCPv4 |
client-arch-type |
61 |
Client System Architecture Type |
DHCPv6 |
client-data |
45 |
Leasequery Reply Client Data |
DHCPv6 |
client-fqdn |
81 |
DHCP Client FQDN |
DHCPv4 |
client-fqdn |
39 |
DHCP Client FQDN |
DHCPv6 |
client-identifier |
1 |
Client Identifier |
DHCPv6 |
client-last-transaction-time |
91 |
Leasequery Client Last Transaction Time |
DHCPv4 |
clt-time |
46 |
Leasequery Client Last Transaction Time |
DHCPv6 |
cookie-servers |
8 |
Cookie Server |
BOOTP |
default-ip-ttl |
23 |
Default IP Time-to-Live |
Host IP |
default-tcp-ttl |
37 |
TCP Default TTL |
Interface |
dhcp-class-identifier |
60 |
Vendor Class Identifier |
DHCPv4 |
dhcp-client-identifier |
61 |
Client-Identifier |
Basic |
dhcp-lease-time |
51 |
IP Address Lease Time |
Lease Information, MS DHCP Client |
dhcp-max-message-size |
57 |
Maximum DHCP Message Size |
DHCPv4 |
dhcp-message-type |
53 |
DHCP Message Type |
DHCPv4 |
dhcp-message |
56 |
Message |
DHCPv4 |
dhcp-option-overload |
52 |
Option Overload |
DHCPv4 |
dhcp-parameter-request-list |
55 |
Parameter Request List |
DHCPv4 |
dhcp-rebinding-time |
59 |
Rebinding (T2) Time Value |
Lease Information, MS DHCP Client |
dhcp-renewal-time |
58 |
Renewing (T1) Time Value |
Lease Information, MS DHCP Client |
dhcp-requested-address |
50 |
Requested IP Address |
DHCPv4 |
dhcp-server-identifier |
54 |
Server Identifier |
DHCPv4 |
dhcp-user-class-id |
77 |
User Class ID |
DHCPv4 |
dns-servers |
23 |
DNS Recursive Name Server |
DHCPv6 |
domain-list |
24 |
Domain Search List |
DHCPv6 |
domain-name |
15 |
Domain Name |
Basic, MS DHCP Client |
domain-name-servers |
6 |
Domain Name Server |
Basic, MS DHCP Client |
domain-search |
119 |
Domain Search |
DHCPv4 |
elapsed-time |
8 |
Elapsed Time |
DHCPv6 |
end |
255 |
End |
-- |
ero |
43 |
Relay Agent Echo Request Option |
DHCPv6 |
erp-local-domain-name |
65 |
Local ERP domain name |
DHCPv6 |
extensions-path |
18 |
Extensions Path |
BOOTP |
finger-servers |
73 |
Finger Server |
Servers |
font-servers |
48 |
X Window System Font Server |
Servers |
geo-conf |
123 |
GeoConf |
DHCPv4 |
geoconf-civic |
99 |
Civic Addresses Configuration |
DHCPv4 |
geoconf-civic |
36 |
Civic Addresses Configuration |
DHCPv6 |
geoloc |
63 |
Geolocation |
DHCPv6 |
host-name |
12 |
Host Name |
Basic |
ia-na |
3 |
Identity Association for Nontemporary Addresses |
DHCPv6 |
ia-pd |
25 |
Prefix Delegation |
DHCPv6 |
ia-ta |
4 |
Identity Association for Temporary Addresses |
DHCPv6 |
iaaddr |
5 |
IA Address |
DHCPv6 |
iaprefix |
26 |
IA Prefix |
DHCPv6 |
ieee802.3-encapsulation |
36 |
Ethernet Encapsulation |
Interface |
impress-servers |
10 |
Impress Server |
BOOTP |
info-refresh-time |
32 |
Information Refresh Time |
DHCPv6 |
interface-id |
18 |
Interface Identifier |
DHCPv6 |
interface-mtu |
26 |
Interface MTU |
Interface |
ip-forwarding |
19 |
IP Forwarding Enable/Disable |
Host IP |
irc-servers |
74 |
IRC Server |
Servers |
isns |
83 |
iSNS |
DHCPv4 |
log-servers |
7 |
Log Server |
Servers |
lpr-servers |
9 |
LPR Server |
Servers |
lq-client-link |
48 |
Leasequery Client Link Reply |
DHCPv6 |
lq-query |
44 |
Leasequery |
DHCPv6 |
lq-relay-data |
47 |
Leasequery Relay Agent Reply |
DHCPv6 |
mask-supplier |
30 |
Mask Supplier |
Interface |
max-dgram-reassembly |
22 |
Maximum Datagram Reassembly Size |
Host IP |
mcns-security-server |
128 |
-- |
Servers |
merit-dump |
14 |
Merit Dump File |
BOOTP |
mobile-ip-home-agents |
68 |
Mobile IP Home Agent |
Servers |
mos-address |
139 |
MoS IPv4 Address |
DHCPv4 |
mos-address |
54 |
MoS IPv6 Address |
DHCPv6 |
mos-fqdn |
140 |
MoS Domain Name List |
DHCPv4 |
mos-fqdn |
55 |
MoS Domain Name List |
DHCPv6 |
name-servers |
5 |
Name Server |
BOOTP |
name-service-search |
117 |
Name Service Search |
DHCPv4 |
nds-context |
87 |
NDS Context |
NetWare Client |
nds-servers |
85 |
NDS Servers |
NetWare Client |
nds-tree |
86 |
NDS Tree Name |
NetWare Client |
netbios-dd-servers |
45 |
NetBIOS over TCP/IP Datagram Distribution Server |
WINS/NetBIOS |
netbios-name-servers |
44 |
NetBIOS over TCP/IP Name Server |
WINS/NetBIOS, MS DHCP Client |
netbios-node-type |
46 |
NetBIOS over TCP/IP Node Type |
WINS/NetBIOS, MS DHCP Client |
netbios-scope |
47 |
NetBIOS over TCP/IP Scope |
WINS/NetBIOS, MS DHCP Client |
netwareip-domain |
62 |
NetWare/IP Domain Name |
NetWare Client |
netwareip-information |
63 |
NetWare/IP Information |
NetWare Client |
new-posix-timezone |
41 |
POSIX time zone string |
DHCPv6 |
new-tzdb-timezone |
42 |
POSIX time zone database name |
DHCPv6 |
nii |
62 |
Client Network Interface Identifier |
DHCPv6 |
nis+-domain |
64 |
NIS+ Domain |
Servers |
nis+-servers |
65 |
Network Information Service (NIS+) Servers |
Servers |
nis-domain |
40 |
NIS Domain |
Servers |
nis-domain-name |
29 |
NIS Domain Name |
DHCPv6 |
nis-servers |
41 |
Network Information Service (NIS) Servers |
Servers |
nis-servers |
27 |
NIS Servers |
DHCPv6 |
nisp-domain-name |
30 |
NIS+ Domain Name |
DHCPv6 |
nisp-servers |
28 |
NIS+ Servers |
DHCPv6 |
nntp-servers |
71 |
NNTP Server |
Servers |
non-local-source-routing |
20 |
Non-Local Source Routing |
Host IP |
ntp-server |
56 |
Message |
DHCPv6 |
ntp-servers |
42 |
NTP Servers |
Servers |
option-time |
8 |
Option Time |
DHCPv6 |
oro |
6 |
Option Request Option |
DHCPv6 |
pad |
0 |
Pad |
-- |
path-mtu-aging-timeout |
24 |
Path MTU Aging Timeout |
Host IP |
path-mtu-plateau-tables |
25 |
Path MTU Plateau Table |
Host IP |
perform-mask-discovery |
29 |
Perform Mask Discovery |
Interface |
policy-filters |
21 |
Policy Filter |
Host IP |
pop3-servers |
70 |
POP3 Server |
Servers |
preference |
7 |
Preference |
DHCPv6 |
pxelinux-config-file |
209 |
Configuration File |
DHCPv4 |
pxelinux-path-prefix |
210 |
Path Prefix |
DHCPv4 |
prelinux-reboot-time |
211 |
Reboot Time |
DHCPv4 |
rapid-commit |
80 |
Rapid Commit |
DHCPv4 |
rapid-commit |
14 |
Rapid Commit |
DHCPv6 |
reconfigure-accept |
20 |
Reconfigure Accept |
DHCPv6 |
reconfigure-message |
19 |
Reconfigure Message |
DHCPv6 |
relay-agent-info |
82 |
DHCP Relay Agent Information |
DHCPv4 |
relay-agent-subscriber-id |
38 |
Relay Agent Subscriber ID |
DHCPv6 |
relay-message |
9 |
Relay Message |
DHCPv6 |
remote-id |
37 |
Relay Agent Remote ID |
DHCPv6 |
resource-location-servers |
11 |
Resource Location Server |
BOOTP |
root-path |
17 |
Root Path |
BOOTP |
router-discovery |
31 |
Perform Router Discovery |
Interface |
router-solicitation-address |
32 |
Router Solicitation Address |
Interface |
routers |
3 |
Router |
Basic, MS DHCP Client |
server-identifier |
2 |
DHCPv6 Server Identifier |
DHCPv6 |
server-unicast |
12 |
Server Unicast |
DHCPv6 |
sip-servers |
120 |
SIP Servers |
DHCPv4 |
sip-servers-name |
21 |
SIP Servers Domain Name List |
DHCPv6 |
sip-servers-address |
22 |
SIP Servers IPv6 Address List |
DHCPv6 |
sip-ua-cs-domains |
141 |
SIP UA Configuration Service Domains |
DHCPv4 |
sip-ua-cs-domains |
58 |
SIP User Agent Configuration Service Domains |
DHCPv6 |
slp-directory agent |
78 |
SLP Directory Agent |
DHCPv4 |
slp-service-scope |
79 |
SLP Service Scope |
DHCPv4 |
smtp-servers |
69 |
SMTP Server |
Servers |
sntp-servers |
31 |
SNTP Configuration |
DHCPv6 |
static-route |
33 |
Static Route |
Interface |
status-code |
13 |
Status Code |
DHCPv6 |
streettalk-directory- assistance-servers |
76 |
STDA Server |
Servers |
streettalk-servers |
75 |
StreetTalk Server |
Servers |
subnet-mask |
1 |
Subnet Mask |
Basic |
subnet-selection |
118 |
Subnet Selection |
DHCPv4 |
swap-server |
16 |
Swap Server |
BOOTP |
tcp-keepalive-garbage |
39 |
TCP Keepalive Garbage |
Interface |
tcp-keepalive-interval |
38 |
TCP Keepalive Interval |
Interface |
tftp-server |
66 |
TFTP Server Name |
Servers |
time-offset |
2 |
Time Offset |
BOOTP |
time-servers |
4 |
Time Server |
BOOTP |
trailer-encapsulation |
34 |
Trailer Encapsulation |
Interface |
tz-database |
101 |
TZ Database String |
DHCPv4 |
tz-posix |
100 |
IEEE 1003.1 String |
DHCPv4 |
user-auth |
98 |
User Authentication |
DHCPv4 |
user-class |
15 |
User Class |
DHCPv6 |
vendor-class |
16 |
Vendor Class |
DHCPv6 |
vendor-encapsulated-options |
43 |
Vendor Specific Information |
DHCPv4 |
vendor-opts |
17 |
Vendor Specific Information |
DHCPv6 |
v-i-vendor-class |
124 |
Vendor Identifying Vendor Class |
DHCPv4 |
v-i-vendor-opts |
125 |
Vendor Identifying Vendor Options |
DHCPv4 |
vpn-id |
185 |
VPN Identifier |
DHCPv4 |
www-servers |
72 |
WWW Server |
Servers |
x-display-managers |
49 |
X Window System Display Manager |
Servers |
6rd |
212 |
6rd |
DHCPv4 |
Option Validation Types
Table B-12 defines the DHCP option validation types. Note that you cannot use some of them to define custom options.
Table B-12 Validation Types
|
Description—Web UI Equivalent)
|
AT_BLOB |
List of binary bytes—binary |
AT_BOOL |
Boolean—boolean |
AT_DATE |
Bytes representing a date—date |
AT_DNSNAME |
DNS name—DNS name |
AT_INT |
Unsigned 32-bit integer—unsigned 32-bit |
AT_INT8 |
8-bit integer—unsigned 8-bit |
AT_INTI |
Unsigned 32-bit integer (Intel)—unsigned 32-bit (Intel) |
AT_IPADDR |
32-bit IP address—IP address |
AT_IP6ADDR |
128-bit IPv6 address—IPv6 address |
AT_MACADDR |
Bytes representing a MAC address—MAC address |
AT_MESSAGE |
Unsigned 8-bit message (not usable for custom options) |
AT_NOLEN |
No length (used for PAD and END only) |
AT_NSTRING |
Sequence of ASCII characters—string |
AT_OVERLOAD |
Overload bytes (not usable for custom options) |
AT_RANGEBYTE |
Range of bytes (not usable for custom options) |
AT_RANGESHORT |
Range of shorts (not usable for custom options) |
AT_RDNSNAME |
Relative DNS name—relative DNS name |
AT_SHORT |
Unsigned 16-bit integer—unsigned 16-bit |
AT_SHRTI |
Unsigned 16-bit integer (Intel)—unsigned 16-bit (Intel) |
AT_SINT |
Signed 32-bit integer—signed 32-bit |
AT_SINT8 |
8-bit integer—signed 8-bit |
AT_SINTI |
Signed 32-bit integer (Intel)—signed 32-bit (Intel) |
AT_SSHORT |
Signed 16-bit integer—signed 16-bit |
AT_SSHRTI |
Signed 16-bit integer (Intel)—signed 16-bit (Intel) |
AT_STIME |
Signed 32-bit signed integer representing time—signed time |
AT_STRING |
Unrestricted sequence of ASCII characters—string |
AT_TIME |
Unsigned 32-bit integer representing time—unsigned time |
AT_TYPECNT |
Type requiring two child definition: size of the type field, and type of data—counted-type: For the DHCPv4 dhcp-user-class-id option (77), the repeating pattern is:
[ len (1 byte) ] [ data, of single type ]
For the DHCPv6 user-class option (15), the repeating pattern is:
[ len (2 byte) ] [ data, of single type ]
|
AT_VENDOR_CLASS |
Vendor-class option (enterprise ID followed by opaque data; if DHCPv4, enterprise ID is followed by EID length)—vendor-class |
AT_VENDOR_OPTS |
Vendor-specific options data (enterprise ID followed by TLVs of vendor-specific data; if DHCPv4, enterprise ID is followed by EID length)—vendor-opts |
AT_ZEROSIZE |
32 bits of zero size (no longer used for PAD and END) |
Note AT_TIME takes the value entered in seconds, by default. For example, if you enter 60, it is taken as 60 seconds and if you enter 60s/60m/2h, it is taken as 60 seconds/60 minutes/2 hours and displayed as 60s/60m/2h.