DHCPv4 Options by Number
The table below shows the DHCPv4 options sorted by option number and includes the validation type. See Table 1 for details on the option validation types found in the Validation column. A 0+ in the Validation column means a repeat count of zero or more occurrences, 1+ means one or more occurrences, 2n means multiple occurrences in multiples of 2.
Tip |
For the syntax for adding more complex option data values for suboptions, see Adding Complex Values for Suboptions. |
No. |
Cisco Prime Network Registrar Name |
Validation |
Description |
---|---|---|---|
0 |
pad |
Used to cause subsequent fields to align on word boundaries. See RFC 2132. |
|
1 |
subnet-mask |
Specifies the client's subnet mask. See RFC 2132. |
|
2 |
time-offset |
Specifies the offset of the client's subnet in seconds from Coordinated Universal Time (UTC). See RFC 2132. |
|
3 |
routers |
AT_IPADDR (1+) |
Specifies a list of IP addresses for routers on the client's subnet. See RFC 2132. |
4 |
time-servers |
AT_IPADDR (1+) |
Specifies a list of RFC 868 [6] time servers available to the client. See RFC 2132. |
5 |
name-servers |
AT_IPADDR (1+) |
Specifies a list of IEN 116 [7] name servers available to the client. See RFC 2132. |
6 |
domain-name-servers |
AT_IPADDR (1+) |
Specifies a list of Domain Name System (STD 13, RFC 1035 [8]) name servers available to the client. See RFC 2132. |
7 |
log-servers |
AT_IPADDR (1+) |
Specifies a list of MIT-LCS UDP log servers available to the client. See RFC 2132. |
8 |
cookie-servers |
AT_IPADDR (1+) |
Specifies a list of RFC 865 [9] cookie servers available to the client. See RFC 2132. |
9 |
lpr-servers |
AT_IPADDR (1+) |
Specifies a list of RFC 1179 [10] line printer servers available to the client. See RFC 2132. |
10 |
impress-servers |
AT_IPADDR (1+) |
Specifies a list of Imagen Impress servers available to the client. See RFC 2132. |
11 |
resource-location-servers |
AT_IPADDR (1+) |
Specifies a list of RFC 887 [11] Resource Location servers available to the client. See RFC 2132. |
12 |
host-name |
Specifies the name of the client. See RFC 2132. |
|
13 |
boot-size |
Specifies the length in 512-octet blocks of the default boot image for the client. See RFC 2132. |
|
14 |
merit-dump |
Specifies the path-name of a file to which the client's core image should be dumped in the event the client crashes. See RFC 2132. |
|
15 |
domain-name |
Specifies the domain name that client should use when resolving hostnames via the Domain Name System. See RFC 2132. |
|
16 |
swap-server |
Specifies the IP address of the client's swap server. See RFC 2132. |
|
17 |
root-path |
Specifies the path-name that contains the client's root disk. See RFC 2132. |
|
18 |
extensions-path |
A string to specify a file, retrievable via TFTP, which contains information which can be interpreted in the same way as the 64-octet vendor-extension field within the BOOTP response, with the following exceptions:
See RFC 2132. |
|
19 |
ip-forwarding |
Specifies whether the client should configure its IP layer for packet forwarding. See RFC 2132. |
|
20 |
non-local-source-routing |
Specifies whether the client should configure its IP layer to allow forwarding of datagrams with non-local source routes. See RFC 2132. |
|
21 |
policy-filters |
AT_IPADDR (2n) |
Specifies policy filters for non-local source routing. See RFC 2132. |
22 |
max-dgram-reassembly |
Specifies the maximum size datagram that the client should be prepared to reassemble. See RFC 2132. |
|
23 |
default-ip-ttl |
Specifies the default time-to-live that the client should use on outgoing datagrams. See RFC 2132. |
|
24 |
path-mtu-aging-timeout |
Specifies the timeout (in seconds) to use when aging Path MTU values discovered by the mechanism defined in RFC 1191 [12]. See RFC 2132. |
|
25 |
path-mtu-plateau-tables |
AT_RANGESHORT (1+) |
Specifies a table of MTU sizes to use when performing Path MTU Discovery as defined in RFC 1191. See RFC 2132. |
26 |
interface-mtu |
Specifies the MTU to use on this interface. See RFC 2132. |
|
27 |
all-subnets-local |
Specifies whether or not the client may 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. See RFC 2132. |
|
28 |
broadcast-address |
Specifies the broadcast address in use on the client's subnet. See RFC 2132. |
|
29 |
perform-mask-discovery |
Specifies whether or not the client should perform subnet mask discovery using ICMP. See RFC 2132. |
|
30 |
mask-supplier |
Specifies whether or not the client should respond to subnet mask requests using ICMP. See RFC 2132. |
|
31 |
router-discovery |
Specifies whether or not the client should solicit routers using the Router Discovery mechanism defined in RFC 1256 [13]. See RFC 2132. |
|
32 |
router-solicitation-address |
Specifies the address to which the client should transmit router solicitation requests. See RFC 2132. |
|
33 |
static-routes |
AT_IPADDR (2n) |
Specifies a list of static routes that the client should install in its routing cache. See RFC 2132. |
34 |
trailer-encapsulation |
Specifies whether or not the client should negotiate the use of trailers (RFC 893 [14]) when using the ARP protocol. See RFC 2132. |
|
35 |
arp-cache-timeout |
Specifies the timeout in seconds for ARP cache entries. See RFC 2132. |
|
36 |
ieee802.3-encapsulation |
Specifies whether or not the client should use Ethernet Version 2 (RFC 894 [15]) or IEEE 802.3 (RFC 1042 [16]) encapsulation if the interface is an Ethernet. See RFC 2132. |
|
37 |
default-tcp-ttl |
Specifies the default TTL that the client should use when sending TCP segments. See RFC 2132. |
|
38 |
tcp-keepalive-interval |
Specifies the interval (in seconds) that the client TCP should wait before sending a keepalive message on a TCP connection. See RFC 2132. |
|
39 |
tcp-keepalive-garbage |
Specifies the whether or not the client should send TCP keepalive messages with a octet of garbage for compatibility with older implementations. See RFC 2132. |
|
40 |
nis-domain |
Specifies the name of the client's NIS domain. See RFC 2132. |
|
41 |
nis-servers |
AT_IPADDR (1+) |
Specifies a list of IP addresses indicating NIS servers available to the client. See RFC 2132. |
42 |
ntp-servers |
AT_IPADDR (1+) |
Specifies a list of IP addresses indicating NTP servers available to the client. See RFC 2132. |
43 |
vendor-encapsulated- options |
See RFC 2132. |
|
44 |
netbios-name-servers |
AT_IPADDR (1+) |
Specifies a list of RFC 1001/1002 [19] [20] NBNS name servers listed in order of preference. See RFC 2132. |
45 |
netbios-dd-servers |
AT_IPADDR (1+) |
Specifies a list of RFC 1001/1002 NBDD servers listed in order of preference. See RFC 2132. |
46 |
netbios-node-type |
Allows NetBIOS over TCP/IP clients which are configurable to be configured as described in RFC 1001/1002. See RFC 2132. |
|
47 |
netbios-scope |
Specifies the NetBIOS over TCP/IP scope parameter for the client as specified in RFC 1001/1002. See RFC 2132. |
|
48 |
font-servers |
(1+) |
Specifies a list of X Window System [21] Font servers available to the client. See RFC 2132. |
49 |
x-display-managers |
(1+) |
Specifies a list of IP addresses of systems that are running the X Window System Display Manager and are available to the client. See RFC 2132. |
50 |
dhcp-requested-address |
Used in a client request (DHCPDISCOVER) to allow the client to request that a particular IP address be assigned. See RFC 2132. |
|
51 |
dhcp-lease-time |
Used in a client request (DHCPDISCOVER or DHCPREQUEST) to allow the client to request a lease time for the IP address. See RFC 2132. |
|
52 |
dhcp-option-overload |
Used to indicate that the DHCP 'sname' or 'file' fields are being overloaded by using them to carry DHCP options. See RFC 2132. |
|
53 |
dhcp-message-type |
Used to convey the type of the DHCP message. See RFC 2132. |
|
54 |
dhcp-server-identifier |
Used in DHCPOFFER and DHCPREQUEST messages, and may optionally be included in the DHCPACK and DHCPNAK messages. See RFC 2132. |
|
55 |
dhcp-parameter-request- list |
AT_INT8 (0+) |
Used by a DHCP client to request values for specified configuration parameters. See RFC 2132. |
56 |
dhcp-message |
Used by a DHCP server to provide an error message to a DHCP client in a DHCPNAK message in the event of a failure. See RFC 2132. |
|
57 |
dhcp-max-message-size |
Specifies the maximum length DHCP message that it is willing to accept. See RFC 2132. |
|
58 |
dhcp-renewal-time |
Specifies the time interval from address assignment until the client transitions to the RENEWING state. See RFC 2132. |
|
59 |
dhcp-rebinding-time |
Specifies the time interval from address assignment until the client transitions to the REBINDING state. See RFC 2132. |
|
60 |
dhcp-class-identifier |
Used by DHCP clients to optionally identify the vendor type and configuration of a DHCP client. See RFC 2132. |
|
61 |
dhcp-client-identifier |
Used by DHCP clients to specify their unique identifier. See RFC 2132. |
|
62 |
netwareip-domain |
Used to convey the NetWare/IP domain name used by the NetWare/IP product. See RFC 2242. |
|
63 |
netwareip-information |
Used to convey all the NetWare/IP related information except for the NetWare/IP domain name. See RFC 2242. |
|
64 |
nis+-domain |
Specifies the name of the client's NIS+ [17] domain. See RFC 2132. |
|
65 |
nis+-servers |
AT_IPADDR (1+) |
Specifies a list of IP addresses indicating NIS+ servers available to the client. See RFC 2132. |
66 |
tftp-server |
Used to identify a TFTP server when the 'sname' field in the DHCP header has been used for DHCP options. See RFC 2132. |
|
67 |
boot-file |
Used to identify a bootfile when the 'file' field in the DHCP header has been used for DHCP options. See RFC 2132. |
|
68 |
mobile-ip-home-agents |
AT_IPADDR (0+) |
Specifies a list of IP addresses indicating mobile IP home agents available to the client. See RFC 2132. |
69 |
smtp-servers |
AT_IPADDR (1+) |
Specifies a list of SMTP servers available to the client. See RFC 2132. |
70 |
pop3-servers |
AT_IPADDR (1+) |
Specifies a list of POP3 available to the client. See RFC 2132. |
71 |
nntp-servers |
AT_IPADDR (1+) |
Specifies a list of NNTP available to the client. See RFC 2132. |
72 |
www-servers |
AT_IPADDR (1+) |
Specifies a list of WWW available to the client. See RFC 2132. |
73 |
finger-servers |
AT_IPADDR (1+) |
Specifies a list of Finger available to the client. See RFC 2132. |
74 |
irc-servers |
AT_IPADDR (1+) |
Specifies a list of IRC available to the client. See RFC 2132. |
75 |
streettalk-servers |
AT_IPADDR (1+) |
Specifies a list of StreetTalk servers available to the client. See RFC 2132. |
76 |
streettalk-directory- assistance-servers |
AT_IPADDR (1+) |
Specifies a list of STDA servers available to the client. See RFC 2132. |
77 |
dhcp-user-class-id |
Used by a DHCP client to optionally identify the type or category of user or applications it represents. See RFC 3004. |
|
78 |
slp-directory-agent |
Specifies the location of one or more SLP Directory Agents. See RFC 2610. |
|
79 |
slp-service-scope |
Comma delimited list which indicates the scopes that a SLP Agent is configured to use. See RFC 2610. |
|
80 |
rapid-commit |
Used to indicate the use of the two-message exchange for address assignment. See RFC 4039. |
|
81 |
client-fqdn |
Client FQDN Option. See RFC 4702. |
|
82 |
relay-agent-info |
A "container" option for specific agent-supplied sub-options. For suboptions, see Table 3. See RFC 3046. |
|
83 |
iSNS |
Specifies the location of the primary and backup iSNS servers and the iSNS services available to an iSNS client. See RFC 4174. |
|
85 |
nds-servers |
AT_IPADDR (1+) |
Specifies one or more NDS servers for the client to contact for access to the NDS database. See RFC 2241. |
86 |
nds-tree |
Specifies the name of the NDS tree the client will be contacting. See RFC 2241. |
|
87 |
nds-context |
Specifies the initial NDS context the client should use. NDS contexts are 16-bit Unicode strings.See RFC 2241. |
|
88 |
bcmcs-servers-d |
AT_DNSNAME (1+) |
Broadcast and Multicast Service Controller Domain Name List for DHCPv4. See RFC 4280. |
89 |
bcmcs-servers-a |
AT_IPADDR (1+) |
Broadcast and Multicast Service Controller IPv4 Address Option for DHCPv4. See RFC 4280. |
90 |
authentication |
DHCP authentication option. See RFC 3118. |
|
91 |
lq-client-last- transaction- time |
Allows the receiver to determine the time of the most recent access of the client. See RFC 4388. |
|
92 |
lq- associated-ip |
AT_IPADDR (1+) |
Used to return all of the IP addresses associated with the DHCP client specified in a particular DHCPLEASEQUERY message. See RFC 4388. |
93 |
pxe-client-arch |
Client System Architecture Type Option Definition. See RFC 4578. |
|
94 |
pxe-client-network-id |
Client Network Interface Identifier Option Definition. See RFC 4578. |
|
95 |
ldap-url |
LDAP Servers. See RFC 3679. |
|
97 |
pxe-client-machine-id |
Client Machine Identifier Option Definition. See RFC 4578. |
|
98 |
user-auth |
Specifies a list of URLs, each pointing to a user authentication service that is capable of processing authentication requests encapsulated in the User Authentication Protocol (UAP). See RFC 2485. |
|
99 |
geoconf-civic |
DHCP Civic Location Option. See RFC 4776. |
|
100 |
posix-timezone |
IEEE 1003.1 TZ String. See RFC 4833. |
|
101 |
tzdb-timezone |
Reference to the TZ Database. See RFC 4833. |
|
108 |
ipv6-only-preferred |
IPv6-Only Preferred Option. See RFC 8925. |
|
109 |
dhcp4o6-s46-saddr |
DHCP 4o6 Softwire Source Address Option. See RFC 8539. |
|
112 |
netinfo-parent-server-addr |
Netinfo Address. See RFC 3679. |
|
113 |
netinfo-parent-server-tag |
Netinfo Tag. See RFC 3679. |
|
114 |
captive-portal |
DHCP Captive-Portal Option. See RFC 8910. |
|
116 |
auto-configure |
Used to ask whether, and be notified if, auto-configuration should be disabled on the local subnet. See RFC 2563. |
|
117 |
name-service-search |
AT_SHORT (1+) |
Name Service Search Option. See RFC 2937. |
118 |
subnet-selection |
Subnet Selection Option. See RFC 3011. |
|
119 |
domain-search |
AT_DNSNAME (1+) |
Domain Search Option. See RFC 3397. |
120 |
sip-servers |
SIP Server DHCP Option. See RFC 3361. |
|
121 |
classless-static-route |
Classless Route Option. See RFC 3442. |
|
122 |
cablelabs-client- configuration |
CableLabs Client Configuration Option (see the Table 3). See RFC 3495. |
|
123 |
geo-conf |
DHCPv4 GeoConf Option. See RFC 6225. |
|
124 |
v-i-vendor-class |
Vendor-Identifying Vendor Class Option. See RFC 3925. |
|
125 |
v-i-vendor-opts |
Vendor-Identifying Vendor-Specific Information Option. See also the cablelabs-125 suboptions in Table 3. See RFC 3925. |
|
128 |
mcns-security-server |
DOCSIS "full security" server IP address. See RFC 4578. |
|
136 |
pana-agent |
AT_IPADDR (1+) |
PANA Authentication Agent DHCPv4 Option. See RFC 5192. |
137 |
lost-server |
LoST Server DHCPv4 Option. See RFC 5223. |
|
138 |
capwap-ac-v4 |
AT_IPADDR (1+) |
CAPWAP AC DHCPv4 Option. See RFC 5417. |
139 |
mos-address |
MoS IPv4 Address Option for DHCPv4. See RFC 5678. |
|
140 |
mos-fqdn |
MoS Domain Name List Option for DHCPv4. See RFC 5678. |
|
141 |
sip-ua-cs-domains |
AT_DNSNAME (0+) |
DHCP SIP User Agent Configuration Service Domains Option. See RFC 6011. |
142 |
andsf-v4 |
ANDSF IPv4 Address Option for DHCPv4. See RFC 6153 |
|
143 |
sztp-redirect |
AT_TYPECNT (0+) |
Used to provision the client with one or more URIs for bootstrap servers that can be contacted to attempt further configuration. See RFC 8572. |
144 |
geoloc |
DHCPv4 GeoLoc Option. See RFC 6225. |
|
145 |
forcerenew-nonce- capable |
AT_INT8 (1+) |
Forcerenew Nonce Protocol Capability Option. See RFC 6704. |
146 |
rdnss-selection |
Used to inform resolvers which RDNSS can be contacted when initiating forward or reverse DNS lookup procedures. See RFC 6731. |
|
147 |
dots-ri |
DHCPv4 DOTS Reference Identifier Option. See RFC 8973. |
|
148 |
dots-address |
AT_IPADDR (1+) |
DHCPv4 DOTS Address Option. See RFC 8973. |
150 |
tftp-server-address |
AT_IPADDR (1+) |
TFTP Server Address Option Definition. See RFC 5859. |
151 |
status-code |
Allows a machine-readable value to be returned regarding the status of a DHCPBULKLEASEQUERY request. See RFC 6926. |
|
152 |
base-time |
Current time the message was created to be sent by the DHCPv4 server to the requestor of the Bulk Leasequery. See RFC 6926. |
|
153 |
start-time-of-state |
Allows the receiver to determine the time at which the IP address made the transition into its current state. See RFC 6926. |
|
154 |
query-start-time |
Specifies a start query time to the DHCPv4 server. See RFC 6926. |
|
155 |
query-end-time |
Specifies an end query time to the DHCPv4 server. See RFC 6926. |
|
156 |
dhcp-state |
Allows greater detail to be returned than allowed by the DHCPLEASEACTIVE and DHCPLEASEUNASSIGNED message types. See RFC 6926. |
|
157 |
data-source |
Contains information about the source of the data in a DHCPLEASEACTIVE or a DHCPLEASEUNASSIGNED message. See RFC 6926. |
|
158 |
v4-pcp-server |
AT_BLOB (1+) |
Used to configure a list of IPv4 addresses of a PCP server. See RFC 7291. |
159 |
v4-portparams |
DHCPv4 Port Parameters Option. See RFC 7618. |
|
160 |
captive-portal-old |
Captive-Portal DHCPv4 Option. See RFC 7710. |
|
161 |
mud-url |
IPv4 MUD URL client option. See RFC 8520. |
|
162 |
cisco-client-requested- host-name |
Cisco Client Requested Host Name. See RFC 3942. |
|
163 |
cisco-client-last- transaction-time |
Cisco Client Last Transaction Time. See RFC 3942. |
|
185 |
vpn-id |
VPN Identifier. See RFC 3942. |
|
209 |
pxelinux-config-file |
Configuration File Option. See RFC 5071. |
|
210 |
pxelinux-path-prefix |
Path Prefix Option. See RFC 5071. |
|
211 |
pxelinux-reboot-time |
Reboot Time Option. See RFC 5071. |
|
212 |
6rd |
6rd DHCPv4 Option. See RFC 5969. |
|
213 |
access-domain |
Access Network Domain Name DHCPv4 Option. See RFC 5986. |
|
220 |
subnet-alloc |
Subnet Allocation Option. See RFC 6656. |
|
221 |
cisco-vpn-id |
DHCPv4 Virtual Subnet Selection Option. See RFC 6607. |
|
251 |
cisco-auto-configure |
Cisco Autoconfiguration Option. |
|
255 |
end |
Marks the end of valid information in the vendor field. See RFC 2132. |