DHCP options

Option value format corresponds to RFC 2132.

Name

Description

1

Subnet mask for the subnet from which the address was received.

2

Time difference between the time of the client subnet and UTC time (specified in seconds).

3

List of IP addresses of available gateways.

6

DNS server list.

7

Log server list (MIT-LCS UDP).

9

LPR server list (RFC 1179).

13

Boot image size for clients.

15

Domain name

16

Swap server.

17

The path to the client root directory.

18

The path to BOOTP extensions.

19

IP datagram forwarding status.

20

Remote source routing status.

21

IP address filtration policy.

22

Datagram maximum size.

23

Default TTL value for IP protocol.

26

MTU value for the given interface.

27

An option showing that all subnets use current MTU configuration.

31

An option which defines using ICMP messages for router detection.

32

Address which is used to access the router.

33

Routing static list; contains pairs "destination address" --- "router address".

34

Using trailers for ARP requests.

35

Timeout for ARP cache memory.

36

An option showing whether it is necessary to use Ethernet data encapsulation.

37

TTL value for TCP packets.

38

Interval for sending TCP control packets (TCP keep-alive).

40

NIS domain.

41

NIS server list.

42

NTP time server list.

44

List of IP addresses of NetBIOS servers.

45

List of IP addresses of NetBIOS datagram forwarding servers.

46

NetBIOS node type.

47

NetBIOS area.

48

IP addresses of X Windows font servers (X Window System Font).

49

X Windows display manager.

58

T1 --- the time interval during which the client should send a request to update the IP address.

59

T2 --- the time interval (in seconds) during which the client should send a request for rebinding.

60

This option is used by DHCP client to set a vendor.

64

NIS+ domain name.

65

NIS+ server list.

66

TFTP server name.

67

Boot file name.

68

Addresses of home agents (Mobile IP Home Agent).

69

SMTP server list.

70

POP3 server list.

71

NNTP server list.

74

IRC server list.

77

User class.

80

This option allows to receive the network settings from the DHCP server by the fast exchange of two messages instead of the usual four messages between the Requesting Router (RR) and the Delegating Router (DR).

93

DHCP client system architecture.

94

DHCP client network interface ID.

97

Client ID based on UUID/GUID.

119

DNS lookup list.

120

SIP server list.

121

The list of classless static routes.

125

This option is used to specify information about a vendor.

255

The end of the option list; must be specified last.