DHCP Option Numbers Table 51. RFC-defined DHCP option numbers and descriptions Option Number Name Description 2 Time Offset Time offset in seconds from UTC 3 Router N/4 router addresses 4 Time Servers N/4 time server addresses 5 Name Servers N/4 IEN-116 server addresses 6 DNS Servers N/4 DNS server addresses 7 Log Servers N/4 logging server addresses 8 Cookie Servers N/4 quote server addresses 9 LPR Servers N/4 printer server addresses 10 Impress Servers N/4 impress server addresses 11 RLP Servers N/4 RLP server addresses 12 Host Name Hostname string 13 Boot File Size Size of boot file in 512 byte chunks 14 Merit Dump File Client to dump and name of file to dump to 15 Domain Name The DNS domain name of the client 16 Swap Server Swap server addresses 17 Root Path Path name for root disk 18 Extension File Patch name for more BOOTP info 19 IP Layer Forwarding Enable or disable IP forwarding 20 Src route enabler Enable or disable source routing 21 Policy Filter Routing policy filters 22 Maximum DG Reassembly Size Maximum datagram reassembly size 23 Default IP TTL Default IP time-to-live 24 Path MTU Aging Timeout Path MTU aging timeout 25 MTU Plateau Path MTU plateau table 26 Interface MTU Size Interface MTU size 27 All Subnets Are Local All subnets are local 28 Broadcast Address Broadcast address 29 Perform Mask Discovery Perform mask discovery 30 Provide Mask to Others Provide mask to others 31 Perform Router Discovery Perform router discovery 32 Router Solicitation Address Router solicitation address 33 Static Routing Table Static routing table 34 Trailer Encapsulation Trailer encapsulation 35 ARP Cache Timeout ARP cache timeout 36 Ethernet Encapsulation Ethernet encapsulation 37 Default TCP Time to Live Default TCP time to live 38 TCP Keepalive Interval TCP keepalive interval 39 TCP Keepalive Garbage TCP keepalive garbage 40 NIS Domain Name NIS domain name 41 NIS Server Addresses NIS server addresses 42 NTP Servers Addresses NTP servers addresses 43 Vendor Specific Information Vendor specific information 44 NetBIOS Name Server NetBIOS name server 45 NetBIOS Datagram Distribution NetBIOS datagram distribution 46 NetBIOS Node Type NetBIOS node type 47 NetBIOS Scope NetBIOS scope 48 X Window Font Server X window font server 49 X Window Display Manager X window display manager 50 Requested IP address Requested IP address 51 IP Address Lease Time IP address lease time 52 Option Overload Overload “sname” or “file” 53 DHCP Message Type DHCP message type 54 DHCP Server Identification DHCP server identification 55 Parameter Request List Parameter request list 56 Message DHCP error message 57 DHCP Maximum Message Size DHCP maximum message size 58 Renew Time Value DHCP renewal (T1) time 59 Rebinding Time Value DHCP rebinding (T2) time 60 Client Identifier Client identifier 61 Client Identifier Client identifier 62 Netware/IP Domain Name Netware/IP domain name 63 Netware/IP sub Options Netware/IP sub options 64 NIS+ V3 Client Domain Name NIS+ V3 client domain name 65 NIS+ V3 Server Address NIS+ V3 server address 66 TFTP Server Name TFTP server name 67 Boot File Name Boot file name 68 Home Agent Addresses Home agent addresses 69 Simple Mail Server Addresses Simple mail server addresses 70 Post Office Server Addresses Post office server addresses 71 Network News Server Addresses Network news server addresses 72 WWW Server Addresses WWW server addresses 73 Finger Server Addresses Finger server addresses 74 Chat Server Addresses Chat server addresses 75 StreetTalk Server Addresses StreetTalk server addresses 76 StreetTalk Directory Assistance Addresses StreetTalk directory assistance addresses 77 User Class Information User class information 78 SLP Directory Agent Directory agent information 79 SLP Service Scope Service location agent scope 80 Rapid Commit Rapid commit 81 FQDN, Fully Qualified Domain Name Fully qualified domain name 82 Relay Agent Information Relay agent information 83 Internet Storage Name Service Internet storage name service 84 Undefined N/A 85 Novell Directory Servers Novell Directory Services servers 86 Novell Directory Server Tree Name Novell Directory Services server tree name 87 Novell Directory Server Context Novell Directory Services server context 88 BCMCS Controller Domain Name List CMCS controller domain name list 89 BCMCS Controller IPv4 Address List BCMCS controller IPv4 address list 90 Authentication Authentication 91 Undefined N/A 92 Undefined N/A 93 Client System Client system architecture 94 Client Network Device Interface Client network device interface 95 LDAP Use Lightweight Directory Access Protocol 96 Undefined N/A 97 UUID/GUID Based Client Identifier UUID/GUID-based client identifier 98 Open Group’s User Authentication Open group’s user authentication 99 Undefined N/A 100 Undefined N/A 101 Undefined N/A 102 Undefined N/A 103 Undefined N/A 104 Undefined N/A 105 Undefined N/A 106 Undefined N/A 107 Undefined N/A 108 Undefined N/A 109 Autonomous System Number Autonomous system number 110 Undefined 111 Undefined 112 NetInfo Parent Server Address NetInfo parent server address 113 NetInfo Parent Server Tag NetInfo parent server tag 114 URL: URL 115 Undefined N/A 116 Auto Configure DHCP auto-configuration 117 Name Service Search Name service search 118 Subnet Collection Subnet selection 119 DNS Domain Search List DNS domain search list 120 SIP Servers DHCP Option SIP servers DHCP option 121 Classless Static Route Option Classless static route option 122 CCC, CableLabs Client Configuration CableLabs client configuration 123 GeoConf GeoConf 124 Vendor-Identifying Vendor Class Vendor-identifying vendor class 125 Vendor Identifying Vendor Specific Vendor-identifying vendor specific 126 Undefined N/A 127 Undefined N/A 128 TFTP Server IP Address TFTP server IP address for IP phone software load 129 Call Server IP Address Call server IP address 130 Discrimination String Discrimination string to identify vendor 131 Remote Statistics Server IP Address Remote statistics server IP address 132 802.1Q VLAN ID IEEE 802.1Q VLAN ID 133 802.1Q L2 Priority IEEE 802.1Q layer 2 priority 134 Diffserv Code Point Diffserv code point for VoIP signalling and media streams 135 HTTP Proxy For Phone Applications HTTP proxy for phone-specific applications 136 Undefined N/A 137 Undefined N/A 138 Undefined N/A 139 Undefined N/A 140 Undefined N/A 141 Undefined N/A 142 Undefined N/A 143 Undefined N/A 144 Undefined N/A 145 Undefined N/A 146 Undefined N/A 147 Undefined N/A 148 Undefined N/A 149 Undefined N/A 150 TFTP Server Address, Etherboot, GRUB Config TFTP server address, Etherboot, GRUB configuration 151 Undefined 152 Undefined N/A 153 Undefined N/A 154 Undefined N/A 155 Undefined N/A 156 Undefined N/A 157 Undefined N/A 158 Undefined N/A 159 Undefined N/A 160 Undefined N/A 161 Undefined N/A 162 Undefined N/A 163 Undefined N/A 164 Undefined N/A 165 Undefined N/A 166 Undefined N/A 167 Undefined N/A 168 Undefined N/A 169 Undefined N/A 170 Undefined N/A 171 Undefined N/A 172 Undefined N/A 173 Undefined N/A 174 Undefined N/A 175 Ether Boot Ether Boot 176 IP Telephone IP telephone 177 Ether Boot PacketCable and CableHome Ether Boot PacketCable and CableHome 178 Undefined N/A 179 Undefined N/A 180 Undefined N/A 181 Undefined N/A 182 Undefined N/A 183 Undefined N/A 184 Undefined N/A 185 Undefined N/A 186 Undefined N/A 187 Undefined N/A 188 Undefined N/A 189 Undefined N/A 190 Undefined N/A 191 Undefined N/A 192 Undefined N/A 193 Undefined N/A 194 Undefined N/A 195 Undefined N/A 196 Undefined N/A 197 Undefined N/A 198 Undefined N/A 199 Undefined N/A 200 Undefined N/A 201 Undefined N/A 202 Undefined N/A 203 Undefined N/A 204 Undefined N/A 205 Undefined N/A 206 Undefined N/A 207 Undefined N/A 208 pxelinux.magic (string) = 241.0.116.126 pxelinux.magic (string) = 241.0.116.126 209 pxelinux.configfile (text) pxelinux.configfile (text) 210 pxelinux.pathprefix (text) pxelinux.pathprefix (text) 211 pxelinux.reboottime pxelinux.reboottime 212 Undefined N/A 213 Undefined N/A 214 Undefined N/A 215 Undefined N/A 216 Undefined N/A 217 Undefined N/A 218 Undefined N/A 219 Undefined N/A 220 Subnet Allocation Subnet allocation 221 Virtual Subnet Allocation Virtual subnet selection 222 Undefined N/A 223 Undefined N/A 224 Private Use Private use 225 Private Use Private use 226 Private Use Private use 227 Private Use Private use 228 Private Use Private use 229 Private Use Private use 230 Private Use Private use 231 Private Use Private use 232 Private Use Private use 233 Private Use Private use 234 Private Use Private use 235 Private Use Private use 236 Private Use Private use 237 Private Use Private use 238 Private Use Private use 239 Private Use Private use 240 Private Use Private use 241 Private Use Private use 242 Private Use Private use 243 Private Use Private use 244 Private Use Private use 245 Private Use Private use 246 Private Use Private use 247 Private Use Private use 248 Private Use Private use 249 Private Use Private use 250 Private Use Private use 251 Private Use Private use 252 Private Use Private use 253 Private Use Private use 254 Private Use Private use