Adding DHCP Options in Mac OS X Server

Mac OS X Server comes with a number of DHCP options available; most notably the options available in the GUI. But what about options that aren’t available in the GUI, such as NTP. Well, using /etc/bootpd.plist, the same file we used to define servers allowed to relay, you can also define other options. These begin with the following keys that can be added into your property list:

  • dhcp_time_offset (option 2)
  • dhcp_router (option 3)
  • dhcp_domain_name_server (option 6)
  • dhcp_domain_name (option 15)
  • dhcp_network_time_protocol_servers (option 42)
  • dhcp_nb_over_tcpip_name_server (option 44)
  • dhcp_nb__over_tcpip_dgram_dist_server (option 45)
  • dhcp_nb_over_tcpip_node_type (option 46)
  • dhcp_nb_over_tcpip_scope (option 47)
  • dhcp_smtp_server (option 69)
  • dhcp_pop3_server (option 70)
  • dhcp_nntp_server (option 71)
  • dhcp_ldap_url (option 95)
  • dhcp_netinfo_server_address (option 112)
  • dhcp_netinfo_server_tag (option 113)
  • dhcp_url (option 114)
  • dhcp_domain_search (option 119)
  • dhcp_proxy_auto_discovery_url (option 252)

But you can also add options by their numerical identifier. To add them, add the following into your /etc/bootpd.plist file and then restart the DHCP service:

<string>dhcp_option_120</string>

<data>

192.168.210.7

</data>

In the above, you’d replace the option 120 (SIP) with the option you wish to use. Numbers correspond to options as follows:
0 – Pad
1 – Subnet Mask
3 – Router
4 – Time Server
5 – Name Server
6 – Domain Name Server
7 – Log Server
8 Quote Server
9 – LPR Server
10 – Impress Server
11 – Resource Location Server
12 – Host Name
13 – Boot File Size
14 – Merit Dump File
15 – Domain Name
16 – Swap Server
17 – Root Path
18 – Extensions Path
19 – IP Forwarding
20 – WAN Source Routing
21 – Policy Filter
22 – Maximum Datagram Reassembly Size
23 – Default IP Time-to-live
24 – Path MTU Aging Timeout
25 – Path MTU Plateau Table
26 – Interface MTU
27 – All Subnets are Local
28 – Broadcast Address
29 – Perform Mask Discovery
30 – Mask supplier
31 – Perform router discovery
32 – Router solicitation address
33 – Static routing table
34 – Trailer encapsulation.
35 – ARP cache timeout
36 – Ethernet encapsulation
37 – Default TCP TTL
38 – TCP keep alive interval
39 – TCP keep alive garbage
40 – Network Information Service Domain
41 – Network Information Servers
42 – NTP servers
43 – Vendor specific information
44 – NetBIOS over TCP/IP name server
45 – NetBIOS over TCP/IP Datagram Distribution Server
46 – NetBIOS over TCP/IP Node Type
47 – NetBIOS over TCP/IP Scope
48 - X Window System Font Server
49 - X Window System Display Manager
50 - Requested IP Address
51 - IP address lease time
52 - Option overload
53 - DHCP message type
54 - Server identifier
55 - Parameter request list
56 - Message
57 - Maximum DHCP message size
58 - Renew time value
59 - Rebinding time value
60 - Class-identifier
61 - Client-identifier
62 - NetWare over IP Domain Name
63 - NetWare over IP information
64 - Network Information Service Domain
65 - Network Information Service Servers
66 - TFTP server name
67 - Bootfile name
68 - Mobile IP Home Agent
69 - Simple Mail Transport Protocol Server
70 - Post Office Protocol Server
71 - Network News Transport Protocol Server
72 - Default World Wide Web Server
73 - Default Finger Server
74 - Default Internet Relay Chat Server
77 - User Class Information
78 - SLP Directory Agent
79 - SLP Service Scope
80 - Rapid Commit
81 - Fully Qualified Domain Name
82 - Relay Agent Information
83 - Internet Storage Name Service
85 - NDS servers
86 - NDS tree name
87 - NDS context
88 - BCMCS Controller Domain Name list
89 - BCMCS Controller IPv4 address list
90 - Authentication
91 - Client Last Transaction Time
92 - Associated IP
93 - Client System Architecture Type
94 - Client Network Interface Identifier
95 - LDAP, Lightweight Directory Access Protocol
97 - Client Machine Identifier
98 - Open Group User Authentication
100 – IEEE 1003.1 TZ String
101 – Reference to the TZ Database
112 – NetInfo Parent Server Address
113 – NetInfo Parent Server Tag
114- URL
116 – Auto-Configure
117 – Name Service Search
118 – Subnet Selection
119 – DNS domain search list
120 – SIP Servers DHCP Option
121 – Classless Static Route Option
123 – GeoConfiguration
124 – Vendor-Identifying Vendor Class
125 – Vendor-Identifying Vendor Specific
128 – TFPT Server IP address
129 – Call Server IP address
130 – Discrimination string
131 – Remote statistics server IP address
132 – 802.1P VLAN ID
133 – 802.1Q L2 Priority
134 – Diffserv Code Point
135 – HTTP Proxy for phone-specific applications
136 – PANA Authentication Agent
139 – IPv4 MoS
140 – IPv4 Fully Qualified Domain Name MoS
150 – TFTP server address
176 – IP Telephone
220 – Subnet Allocation
221 – Virtual Subnet Selection
252 – Proxy auto-discovery
254 – Private use
255 – End
  • Bogdan

    Ok, I can add options into server… But how I can add such options on client(Mac OS 10.6) – I need option 121 but Mac OS doesn’t support it.

  • matthijs

    Same problem as Bogdan.. option 121 is not accepted by OSX client (10.6)… please assist

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  • Tim

    Hi, does it matter where in the bootpd.plist the option gets added? I am trying to add option 184 for 3Com Phone system NCP IP address. Thanks!

    • http://www.krypted.com Charles

      Shouldn’t matter where it goes.

  • newbie

    Hi

    Im using Mac OS X Snow Leopard server. i need to configure option 43 to issue ip to the lightweight AP

    I have scope the ip range and also have the wlc interface ip

    dhcp_option_43

    wlc interce ip

    is this the correct way to add the above part to bootpd.plist?

    • http://www.krypted.com Charles

      Where are you putting it in the config file?

  • newbie

    ” dhcp_option_43

    wlc ip

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