DHCP Option Reference & Builder
Browse RFC 2132 DHCP options and build hex payloads for option 43, 60, 66, 67, and 51 - VoIP phone and router provisioning with ISC dhcpd output. Free.
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What is DHCP Option Reference & Builder?
DHCP Option Reference lists the most-used RFC 2132 DHCP options with their codes, types, and purposes, and includes a builder that encodes option 43, 60, 66, 67, and 51 payloads into the hex bytes VoIP phones and routers expect - complete with a ready-to-paste ISC dhcpd configuration line.
Key Benefits
- Provision VoIP phones and APs without hand-computing hex
- Option table doubles as an offline troubleshooting reference
- ISC dhcpd config line is ready to paste, format-free
- Byte-order-correct encoding for strings and uint32 values
- Instant and offline - encoding happens in your browser
Common Use Cases
- •Rolling out IP phones that discover their TFTP server via option 66
- •Configuring PXE boot entries with options 66 and 67
- •Setting classless static routes with option 121 on a router
- •Teaching network engineers the DHCP option landscape
How to Build a DHCP Option Payload
- Find the option: Search the reference table by code or name to confirm the option number and type.
- Enter the value: Pick the option in the builder and type the value - text for 43/60/66/67, seconds for lease time.
- Copy the payload: Copy the hex bytes or the ready ISC dhcpd config line into your DHCP server configuration.
Key Features
- 25 most-used RFC 2132 options with codes, types, and descriptions
- Instant filtering by option code or name
- Hex payload builder for options 43, 60, 66, 67, and 51
- Proper byte-order encoding for strings and uint32 values
- Copy-ready hex plus the matching ISC dhcpd config line
- Instant, offline encoding - nothing leaves your browser
Frequently Asked Questions
What is DHCP option 43 used for?
Vendor-specific information - typically hex-encoded provisioning details for VoIP phones, access points, and other embedded devices that discover their controllers or config servers through DHCP.
Which options matter for VoIP phone provisioning?
Option 66 (TFTP server name), option 67 (bootfile name), option 150 (TFTP server IP on Cisco), and often option 43 for vendor-specific controller addresses.
Is the hex output compatible with my DHCP server?
The hex bytes are universal; the ISC dhcpd line uses the standard code-N declaration syntax. Windows Server and router UIs accept the same hex with their own entry forms.
Does the tool need network access?
No. The option table and encoding are bundled with the page - everything works offline.