| Tag | Name | Data Length | Meaning | Reference |
|---|---|---|---|---|
| 0 | Pad | 0 | None | [RFC2132] |
| 1 | Subnet Mask | 4 | Subnet Mask Value | [RFC2132] |
| 2 | Time Offset | 4 | Time Offset in Seconds from UTC (note: deprecated by 100 and 101) | [RFC2132] |
| 3 | Router | N | N/4 Router addresses | [RFC2132] |
| 4 | Time Server | N | N/4 Timeserver addresses | [RFC2132] |
| 5 | Name Server | N | N/4 IEN-116 Server addresses | [RFC2132] |
| 6 | Domain Server | N | N/4 DNS Server addresses | [RFC2132] |
| 7 | Log Server | N | N/4 Logging Server addresses | [RFC2132] |
| 8 | Quotes Server | N | N/4 Quotes Server addresses | [RFC2132] |
| 9 | LPR Server | N | N/4 Printer Server addresses | [RFC2132] |
| 10 | Impress Server | N | N/4 Impress Server addresses | [RFC2132] |
| 11 | RLP Server | N | N/4 RLP Server addresses | [RFC2132] |
| 12 | Hostname | N | Hostname string | [RFC2132] |
| 13 | Boot File Size | 2 | Size of boot file in 512 byte chunks | [RFC2132] |
| 14 | Merit Dump File | N | Client to dump and name the file to dump it to | [RFC2132] |
| 15 | Domain Name | N | The DNS domain name of the client | [RFC2132] |
| 16 | Swap Server | N | Swap Server address | [RFC2132] |
| 17 | Root Path | N | Path name for root disk | [RFC2132] |
| 18 | Extension File | N | Path name for more BOOTP info | [RFC2132] |
| 19 | Forward On/Off | 1 | Enable/Disable IP Forwarding | [RFC2132] |
| 20 | SrcRte On/Off | 1 | Enable/Disable Source Routing | [RFC2132] |
| 21 | Policy Filter | N | Routing Policy Filters | [RFC2132] |
| 22 | Max DG Assembly | 2 | Max Datagram Reassembly Size | [RFC2132] |
| 23 | Default IP TTL | 1 | Default IP Time to Live | [RFC2132] |
| 24 | MTU Timeout | 4 | Path MTU Aging Timeout | [RFC2132] |
| 25 | MTU Plateau | N | Path MTU Plateau Table | [RFC2132] |
| 26 | MTU Interface | 2 | Interface MTU Size | [RFC2132] |
| 27 | MTU Subnet | 1 | All Subnets are Local | [RFC2132] |
| 28 | Broadcast Address | 4 | Broadcast Address | [RFC2132] |
| 29 | Mask Discovery | 1 | Perform Mask Discovery | [RFC2132] |
| 30 | Mask Supplier | 1 | Provide Mask to Others | [RFC2132] |
| 31 | Router Discovery | 1 | Perform Router Discovery | [RFC2132] |
| 32 | Router Request | 4 | Router Solicitation Address | [RFC2132] |
| 33 | Static Route | N | Static Routing Table | [RFC2132] |
| 34 | Trailers | 1 | Trailer Encapsulation | [RFC2132] |
| 35 | ARP Timeout | 4 | ARP Cache Timeout | [RFC2132] |
| 36 | Ethernet | 1 | Ethernet Encapsulation | [RFC2132] |
| 37 | Default TCP TTL | 1 | Default TCP Time to Live | [RFC2132] |
| 38 | Keepalive Time | 4 | TCP Keepalive Interval | [RFC2132] |
| 39 | Keepalive Data | 1 | TCP Keepalive Garbage | [RFC2132] |
| 40 | NIS Domain | N | NIS Domain Name | [RFC2132] |
| 41 | NIS Servers | N | NIS Server Addresses | [RFC2132] |
| 42 | NTP Servers | N | NTP Server Addresses | [RFC2132] |
| 43 | Vendor Specific | N | Vendor Specific Information | [RFC2132] |
| 44 | NETBIOS Name Srv | N | NETBIOS Name Servers | [RFC2132] |
| 45 | NETBIOS Dist Srv | N | NETBIOS Datagram Distribution | [RFC2132] |
| 46 | NETBIOS Node Type | 1 | NETBIOS Node Type | [RFC2132] |
| 47 | NETBIOS Scope | N | NETBIOS Scope | [RFC2132] |
| 48 | X Window Font | N | X Window Font Server | [RFC2132] |
| 49 | X Window Manager | N | X Window Display Manager | [RFC2132] |
| 50 | Address Request | 4 | Requested IP Address | [RFC2132] |
| 51 | Address Time | 4 | IP Address Lease Time | [RFC2132] |
| 52 | Overload | 1 | Overload "sname" or "file" | [RFC2132] |
| 53 | DHCP Msg Type | 1 | DHCP Message Type | [RFC2132] |
| 54 | DHCP Server Id | 4 | DHCP Server Identification | [RFC2132] |
| 55 | Parameter List | N | Parameter Request List | [RFC2132] |
| 56 | DHCP Message | N | DHCP Error Message | [RFC2132] |
| 57 | DHCP Max Msg Size | 2 | DHCP Maximum Message Size | [RFC2132] |
| 58 | Renewal Time | 4 | DHCP Renewal (T1) Time | [RFC2132] |
| 59 | Rebinding Time | 4 | DHCP Rebinding (T2) Time | [RFC2132] |
| 60 | Class Id | N | Class Identifier | [RFC2132] |
| 61 | Client Id | N | Client Identifier | [RFC2132] |
| 62 | NetWare/IP Domain | N | NetWare/IP Domain Name | [RFC2242] |
| 63 | NetWare/IP Option | N | NetWare/IP sub Options | [RFC2242] |
| 64 | NIS-Domain-Name | N | NIS+ v3 Client Domain Name | [RFC2132] |
| 65 | NIS-Server-Addr | N | NIS+ v3 Server Addresses | [RFC2132] |
| 66 | Server-Name | N | TFTP Server Name | [RFC2132] |
| 67 | Bootfile-Name | N | Boot File Name | [RFC2132] |
| 68 | Home-Agent-Addrs | N | Home Agent Addresses | [RFC2132] |
| 69 | SMTP-Server | N | Simple Mail Server Addresses | [RFC2132] |
| 70 | POP3-Server | N | Post Office Server Addresses | [RFC2132] |
| 71 | NNTP-Server | N | Network News Server Addresses | [RFC2132] |
| 72 | WWW-Server | N | WWW Server Addresses | [RFC2132] |
| 73 | Finger-Server | N | Finger Server Addresses | [RFC2132] |
| 74 | IRC-Server | N | Chat Server Addresses | [RFC2132] |
| 75 | StreetTalk-Server | N | StreetTalk Server Addresses | [RFC2132] |
| 76 | STDA-Server | N | ST Directory Assist. Addresses | [RFC2132] |
| 77 | User-Class | N | User Class Information | [RFC3004] |
| 78 | Directory Agent | N | directory agent information | [RFC2610] |
| 79 | Service Scope | N | service location agent scope | [RFC2610] |
| 80 | Rapid Commit | 0 | Rapid Commit | [RFC4039] |
| 81 | Client FQDN | N | Fully Qualified Domain Name | [RFC4702] |
| 82 | Relay Agent Information | N | Relay Agent Information | [RFC3046] |
| 83 | iSNS | N | Internet Storage Name Service | [RFC4174] |
| 84 | REMOVED/Unassigned | [RFC3679] | ||
| 85 | NDS Servers | N | Novell Directory Services | [RFC2241] |
| 86 | NDS Tree Name | N | Novell Directory Services | [RFC2241] |
| 87 | NDS Context | N | Novell Directory Services | [RFC2241] |
| 88 | BCMCS Controller Domain Name list | [RFC4280] | ||
| 89 | BCMCS Controller IPv4 address option | [RFC4280] | ||
| 90 | Authentication | N | Authentication | [RFC3118] |
| 91 | client-last-transaction-time option | [RFC4388] | ||
| 92 | associated-ip option | [RFC4388] | ||
| 93 | Client System | N | Client System Architecture | [RFC4578] |
| 94 | Client NDI | N | Client Network Device Interface | [RFC4578] |
| 95 | LDAP | N | Lightweight Directory Access Protocol | [RFC3679] |
| 96 | REMOVED/Unassigned | [RFC3679] | ||
| 97 | UUID/GUID | N | UUID/GUID-based Client Identifier | [RFC4578] |
| 98 | User-Auth | N | Open Group's User Authentication | [RFC2485] |
| 99 | GEOCONF_CIVIC | [RFC4776] | ||
| 100 | PCode | N | IEEE 1003.1 TZ String | [RFC4833] |
| 101 | TCode | N | Reference to the TZ Database | [RFC4833] |
| 102-107 | REMOVED/Unassigned | [RFC3679] | ||
| 108 | REMOVED/Unassigned | [RFC3679] | ||
| 109 | Unassigned | [RFC3679] | ||
| 110 | REMOVED/Unassigned | [RFC3679] | ||
| 111 | Unassigned | [RFC3679] | ||
| 112 | Netinfo Address | N | NetInfo Parent Server Address | [RFC3679] |
| 113 | Netinfo Tag | N | NetInfo Parent Server Tag | [RFC3679] |
| 114 | URL | N | URL | [RFC3679] |
| 115 | REMOVED/Unassigned | [RFC3679] | ||
| 116 | Auto-Config | N | DHCP Auto-Configuration | [RFC2563] |
| 117 | Name Service Search | N | Name Service Search | [RFC2937] |
| 118 | Subnet Selection Option | 4 | Subnet Selection Option | [RFC3011] |
| 119 | Domain Search | N | DNS domain search list | [RFC3397] |
| 120 | SIP Servers DHCP Option | N | SIP Servers DHCP Option | [RFC3361] |
| 121 | Classless Static Route Option | N | Classless Static Route Option | [RFC3442] |
| 122 | CCC | N | CableLabs Client Configuration | [RFC3495] |
| 123 | GeoConf Option | 16 | GeoConf Option | [RFC6225] |
| 124 | V-I Vendor Class | Vendor-Identifying Vendor Class | [RFC3925] | |
| 125 | V-I Vendor-Specific Information | Vendor-Identifying Vendor-Specific Information | [RFC3925] | |
| 126 | Removed/Unassigned | [RFC3679] | ||
| 127 | Removed/Unassigned | [RFC3679] | ||
| 128 | PXE - undefined (vendor specific) | [RFC4578] | ||
| 128 | Etherboot signature. 6 bytes: E4:45:74:68:00:00 | |||
| 128 | DOCSIS "full security" server IP address | |||
| 128 | TFTP Server IP address (for IP Phone software load) | |||
| 129 | PXE - undefined (vendor specific) | [RFC4578] | ||
| 129 | Kernel options. Variable length string | |||
| 129 | Call Server IP address | |||
| 130 | PXE - undefined (vendor specific) | [RFC4578] | ||
| 130 | Ethernet interface. Variable length string. | |||
| 130 | Discrimination string (to identify vendor) | |||
| 131 | PXE - undefined (vendor specific) | [RFC4578] | ||
| 131 | Remote statistics server IP address | |||
| 132 | PXE - undefined (vendor specific) | [RFC4578] | ||
| 132 | IEEE 802.1Q VLAN ID | |||
| 133 | PXE - undefined (vendor specific) | [RFC4578] | ||
| 133 | IEEE 802.1D/p Layer 2 Priority | |||
| 134 | PXE - undefined (vendor specific) | [RFC4578] | ||
| 134 | Diffserv Code Point (DSCP) for VoIP signalling and media streams | |||
| 135 | PXE - undefined (vendor specific) | [RFC4578] | ||
| 135 | HTTP Proxy for phone-specific applications | |||
| 136 | OPTION_PANA_AGENT | [RFC5192] | ||
| 137 | OPTION_V4_LOST | [RFC5223] | ||
| 138 | OPTION_CAPWAP_AC_V4 | N | CAPWAP Access Controller addresses | [RFC5417] |
| 139 | OPTION-IPv4_Address-MoS | N | a series of suboptions | [RFC5678] |
| 140 | OPTION-IPv4_FQDN-MoS | N | a series of suboptions | [RFC5678] |
| 141 | SIP UA Configuration Service Domains | N | List of domain names to search for SIP User Agent Configuration | [RFC6011] |
| 142 | OPTION-IPv4_Address-ANDSF | N | ANDSF IPv4 Address Option for DHCPv4 | [RFC6153] |
| 143 | OPTION-IPv6_Address-ANDSF | N | ANDSF IPv6 Address Option for DHCPv6 | [RFC6153] |
| 144 | GeoLoc | 16 | Geospatial Location with Uncertainty | [RFC6225] |
| 145 | FORCERENEW_NONCE_CAPABLE | 1 | Forcerenew Nonce Capable | [RFC-ietf-dhc-forcerenew-nonce-07] |
| 146-149 | Unassigned | [RFC3942] | ||
| 150 | TFTP server address | [RFC5859] | ||
| 150 | Etherboot | |||
| 150 | GRUB configuration path name | |||
| 151-174 | Unassigned | [RFC3942] | ||
| 175 | Etherboot (Tentatively Assigned - 2005-06-23) | |||
| 176 | IP Telephone (Tentatively Assigned - 2005-06-23) | |||
| 177 | Etherboot (Tentatively Assigned - 2005-06-23) | |||
| 177 | PacketCable and CableHome (replaced by 122) | |||
| 178-207 | Unassigned | [RFC3942] | ||
| 208 | PXELINUX Magic | 4 | magic string = F1:00:74:7E | [RFC5071][Deprecated] |
| 209 | Configuration File | N | Configuration file | [RFC5071] |
| 210 | Path Prefix | N | Path Prefix Option | [RFC5071] |
| 211 | Reboot Time | 4 | Reboot Time | [RFC5071] |
| 212 | OPTION_6RD | 18 + N | OPTION_6RD with N/4 6rd BR addresses | [RFC5969] |
| 213 | OPTION_V4_ACCESS_DOMAIN | N | Access Network Domain Name | [RFC5986] |
| 214-219 | Unassigned | |||
| 220 | Subnet Allocation Option | N | Subnet Allocation Option | [draft-ietf-dhc-subnet-alloc-13] |
| 221 | Virtual Subnet Selection (VSS) Option | [RFC6607] | ||
| 222-223 | Unassigned | [RFC3942] | ||
| 224-254 | Reserved (Private Use) | |||
| 255 | End | 0 | None | [RFC2132] |
转载自IANA