Table 197: DHCP/BOOTP Options: Application and Service Parameters 
| Code Value | Data Length 
(bytes) | Name 
and Description | 
| 40 | Variable | Network Information Service 
Domain: Specifies the client's NIS domain. Contrast to option 
#64. | 
| 41 | Variable 
(Multiple of 4) | Network 
Information Servers: Specifies a list of IP addresses of NIS 
servers the client may use. Servers are listed in the order of preference 
for the client to use. Contrast to option #65. | 
| 42 | Variable (Multiple 
of 4) | Network Time Protocol Servers: 
Specifies a list of IP addresses of Network 
Time Protocol servers the client may use. 
Servers are listed in the order of preference for the client to use. | 
| 43 | Variable | Vendor 
Specific Information: Allows an arbitrary set of vendor-specific 
information to be included as a single option within a DHCP or BOOTP 
message. This information is structured using the same format as the 
Options or Vend field itself, except that it does not start with a magic 
cookie. See the end of the 
previous topic for more details. | 
| 44 | Variable (Multiple 
of 4) | NetBIOS Over TCP/IP Name 
Servers: Specifies a list of IP addresses of NetBIOS 
name servers (per RFC 1001/1002) that the client may use. Servers are 
listed in the order of preference for the client to use. | 
| 45 | Variable 
(Multiple of 4) | NetBIOS 
Over TCP/IP Datagram Distribution Servers: Specifies a list 
of IP addresses of NetBIOS datagram distribution servers (per RFC 1001/1002) 
that the client may use. Servers are listed in the order of preference 
for the client to use. | 
| 46 | 1 |     | 
| 47 | Variable | NetBIOS 
Over TCP/IP Scope: Specifies the NetBIOS 
over TCP/IP scope parameter for the client. | 
| 48 | Variable (Multiple 
of 4) | X Window System Font Servers: 
Specifies a list of IP addresses of X Window System Font servers that 
the client may use. Servers are listed in the order of preference for 
the client to use. | 
| 49 | Variable 
(Multiple of 4) | X Window 
System Display Manager: Specifies a list of IP addresses of 
systems running the X Window System Display Manager that the client 
may use. Addresses are listed in the order of preference for the client 
to use. | 
| 64 | Variable | Network Information Service+ 
Domain: Specifies the client's NIS+ domain. Contrast to option 
#40. | 
| 65 | Variable 
(Multiple of 4) | Network 
Information Service+ Servers: Specifies a list of IP addresses 
of NIS+ servers the client may use. Servers are listed in the order 
of preference for the client to use. Contrast to option #41. | 
| 68 | Variable (Multiple 
of 4) | Mobile IP Home Agent: 
Specifies a list of IP addresses of home 
agents that the client can use in Mobile 
IP. Agents are listed in the order of 
preference for the client to use; normally a single agent is specified. | 
| 69 | Variable 
(Multiple of 4) | Simple 
Mail Transport Protocol (SMTP) Servers: Specifies a list of 
IP addresses of SMTP 
servers the client may use. Servers are listed in the order of preference 
for the client to use. | 
| 70 | Variable (Multiple 
of 4) | Post Office Protocol (POP3) 
Servers: Specifies a list of IP addresses of POP3 
servers the client may use. Servers are listed in the order of preference 
for the client to use. | 
| 71 | Variable 
(Multiple of 4) | Network 
News Transfer Protocol (NNTP) Servers: Specifies a list of IP 
addresses of NNTP 
servers the client may use. Servers are listed in the order of preference 
for the client to use. | 
| 72 | Variable (Multiple 
of 4) | Default World Wide Web 
(WWW) Servers: Specifies a list of IP addresses of World 
Wide Web (HTTP) servers the client may 
use. Servers are listed in the order of preference for the client to 
use. | 
| 73 | Variable 
(Multiple of 4) | Default 
Finger Servers: Specifies a list of IP addresses of Finger servers 
the client may use. Servers are listed in the order of preference for 
the client to use. | 
| 74 | Variable (Multiple 
of 4) | Default Internet Relay 
Chat (IRC) Servers: Specifies a list of IP addresses of Internet 
Relay Chat (IRC) servers the client may 
use. Servers are listed in the order of preference for the client to 
use. | 
| 75 | Variable 
(Multiple of 4) | StreetTalk 
Servers: Specifies a list of IP addresses of StreetTalk servers 
the client may use. Servers are listed in the order of preference for 
the client to use. | 
| 76 | Variable (Multiple 
of 4) | StreetTalk Directory Assistance 
(STDA) Servers: Specifies a list of IP addresses of STDA servers 
the client may use. Servers are listed in the order of preference for 
the client to use. |