DHCPv4 Option Summary

Option Name Code ISC Option Name Microsoft Option Name Descritpion All subnets are local 27 all-subnets-local All subnets are local 0 specifies that the client should assume that some IP subnets have smaller MTUs; 1 specifies that all subnets have same MTU as subnet to which the client is connected. ARP cache timeout 35 arp-cache-timeout ARP cache Timeout Timeout (in seconds) for ARP cache entries Autoconfiguration 116 autoconfiguration 0 specifies that the client should not perform link-local IP address autoconfiguration; 1 specifies that the client should perform autoconfiguration Boot file size 13 boot-size Boot file size Size of the client bootfile in 512-byte blocks Boot file name 67 bootfile-name Boot file name Name of the bootfile to use when the file field is used to carry options Broadcast address 28 Broadcast-address Broadcast address The broadcast address for the subnet to which the client is attached. Client identifier 61 Dhcp-client-identifier Client’s unique identifier Cookie server 8 Cookie-servers Cookie servers Cookie servers Default IP TTL 23 Default-ip-ttl Default Time-to-Live Default TTL client should use for outgoing  datagrams Dhcp authentication option 90 authentication Option used to authenticate DHCP packets transmitted by client and servers DHCP message type 53 Dhcp-message-type Identifies the type of the DHCP message Domain name servers 6 Domain-name-servers Dns server List of DNS server IP addresses Domain name 15 Domain-name Domain name Default name for DNS name resolution. End  255 Option-end Indicates end of options in field Ethernet encapsulation 36 Ieee802-3-encapsulation Ethernet encapsulation 0 specifies Ethernet version 2 encapsulation; 1 specifies IEEE 802.3 Extensions path 18 Extensions-path Extensions path The name of the file containing additional options to be interpreted according to RFC2132 format Finger server 73 Finger-server Finger servers List of finger server IP addresses Host name 12 Host-name Host name Client hostname Impress server 10 Impress-servers Impress servers Imagen impress printer servers Interface MTU 26 Interface-mtu MTU option Value of MTU that the client should use for this interface Length of DHCP lease 51 Dhcp-lease-time Lease duration (expressed in seconds) for the assigned IP address IP forwarding 19 Ip-forwarding IP Layer Forwarding 0 specifies that datagram forwarding between interfaces is to be disabled; 1 specifies that forwarding is to be enabled IRC Server 74 Irc-server Internet relay chat (IRC) servers List of internet relay chat server IP address Log server 7 Log-servers Log servers MIT-LCS log servers LPR server 9 Lpr-servers LPR Servers LPDP servers Mask supplier 30 Mask-supplier Mask Supplier Option 0 specifies that the client should not respond to ICMP subnet mask request messages; 1 specifies that the client should respond. Maximum datagram 22 Max-dgram-reassembly Max DG Reassembly Size Maximum size of datagram that reassembly the client should expect to reassemble Maximum DHCP 57 Dhcp-max-message-size Maximum DHCP message size message size accepted by the client Merit dump file 14 Merit-dump Merit dump file Name of file for memory dump Message 56 Dhcp-message Message from the server to be displayed to the user by the client Mobile IP home agents 68 Mobile-ip-home-agents Mobile IP home agents List of mobile IP home agents Name server 5 Ien116-name-servers Name Servers IEN 116 name servers Name Service 117 Name-service-search-order Ordered list of name service types that the client should use initial netware directory server (NDS) for client NDS Server 85 Nds-servers List of NDS servers NDS tree name 86 Nds-tree-name NDS tree name for the client to use. NetBIOS over TCP/IP 45 Netbios-dd-server NetBIOS over TCP/IP NBDD List of NetBIOS Datagram data-Distribution(NBDD) servers NetBIOS over TCP/IP name server 44 Netbios-name-servers WINS/NBNS servers List of NetBIOS Name Server(NBNS) IP addresses.

Option Name Code ISC Option Name Microsoft Option Name Descritpion NetBIOS over TCP/IP type 46 Netbios-node-type WINS/NBT type Client’s NetBIOS over TCP/IP node NetBIOS over TCP/IP scope 47 Netbios-scope NetBIOS scope ID Client’s NetBIOS over TCP/IP scope NetWare/IP domain 62 Nwip-domain Name of NetWare/IP domain for client NetWare/IP information 63 Nwip.nsq-broadcast nwip.preferred-dss nwip.nearest-nwip-server nwip.autoretries nwip.autoretry-secs nwip.nwip-1-1 nwip.primary-dss NetWare/IP parameters NIS domain Name 40 Nis-domain NIS Domain Name Client’s Network Information Service (NIS) domain NIS Servers 41 Nis-servers NIS Servers List of NIS servers NIS+ domain Name 64 Nisplus-domain NIS+ Domain Name Client’s Network information Server+(NIS+) domain NIS+ servers 65 Nisplus-servers Nis+ servers List of NIS+ server IP addresses NNTP server 71 nntp-server Network News Transport Protocol (NNTP) servers List of NNTP servers Non-local source routing 20 Non-local-source-routing Non-local source routing 0 specifies that forwarding of datagrams with nonlocal source routes is to be disallowed; 1 specifies that forwarding of sub datagrams is to be allowed NTP servers 42 Ntp-servers NTP server Lsit of network Time Protocol (NTP) servers Option overload 52 Dhcp-option-overload Specifies whether file and sname fields are used to carry options Pad 0 Pad Carries no data Parameters request list 55 Dhcp-parameter-request-list List of options requested by the client Path MTU aging 24 Path-mtu-aging-seconds Path MTU Aging Timeout Timeout(in seconds) for aging PMTU values Path MTU plateau table 25 Path-mtu-plateau-table Path MTU Plateau Table List of MTU sizes for PMTU discovery. Perform mask discovery 29 Perform-mask-discovery Perform mask discovery 0 specifies that the client should not perform ICMP subnet mask discovery; 1 specifies that the client should perform subnet mask discovery Policy filter 21 Policy-filter Policy Filter Masks List of policy filters for nonlocal source routing. POP3 server 70 Pop-server (pop3) server IP Post office protocol (pop3) servers List of post office protocol 3 addresses Requested IP address 50 Dhcp-requested-address IP address requested by the client. Relay agent information the relay option 82 Relay-agent-information Additional information supplied by agent Resource location servers 11 Resource-location-servers servers Resource location servers Resource location protocol Root path 17 Root-path Root path Name of the client’s root disk. Router solicitation for router 32 Router-solicitation-address Router solicitation The address the client should use address discovery Routers 3 routers router IP addresses of default routers to use on the client’s network segment Server identifier 54 Dhcp-server-identifier The IP address of the DHCP server SLP Directory Agent 78 Slp-directory-agent The service location Protocol service scope SMTP server 69 Smtp-server Simple mail transport protocol (SMTP) servers List of simple mail transport protocol (SMTP) servers Static route 33 Static-routes Static route option List of static routes; each static route includes a destination Streettalk directory assistance server 76 Streettalk-directory-assistance -server Streettalk directory assistance (STDA) servers List of STDA servers Subnet mask 1 Subnet-mask The subnet mask for the network segment to which the client is connected. Subnet selection option 118 Subnet-selection The subnet number to use in selecting the client IP address. Swap server 16 Swap-server Swap server The swap server for the client T1 58 Dhcp-renewal-time The time, in seconds ,until the client should renew the lease on the assigned address. T2 59 Dhcp-rebinding-time The time, in seconds, until the client should rebind the lease on the assigned address. TCP default TTL 37 Default-tcp-ttl Default TTL option The default TTL for TCP segments TCP keepalive garbage 39 Tcp-keepalive-garbage Keepalive Garbage 0 specifies that the client should not send a garbage byte with a TCP keepalive message; 1 specifies that the client should send a garbage byte TCP keepalive interval 38 Tcp-keepalive-interval Keepalive interval The time, in seconds, to wait before sending a keepalive message on a TCP connection TFTP server name 66 Tftp-server-name Boot server Host name The name of the TFTP serve r to use when the Sname field is used to carry options Time offset 2 Time-offset Time offset The time offset, in seconds, from coordinated universal time (UTC) for the client’s network segment Time server 4 Time-servers Time server The time server’s IP addresses Trailer 34 Trailer-encapsulation Trailer encapsulation 0 specifies that the client should not negotiate the use of trailers through ARP; 1 specifies that the client should negotiate the use of trailers. UAP servers 98 Uap-servers List of URLs specifying User authentication protocol servers User class 77 User class User class information Vendor class identifier 60 Vendor-class-identifier Vendor identification Vendor specific information 43 Vendor-encapsulated-options Vendor specific info Vendor-specific information WWW server 72 www-server World wide web(WWW) servers List of world web server IP addresses X window system display managers 49 x-display-managers X window system display List of X window system display manager X window system font server 48 Font-servers X window system font List of x window system font servers