Fields

Field pages explain one header element precisely: definition, bit width, common values, and how it affects behavior. Use this index when you already know the protocol but need the exact meaning of a single field.

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Field Tabs

Switch protocol groups. Search filters only inside the current tab.

→ Protocol Dictionary → Topics index → Tools index

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How to use

1) From a capture, identify the protocol (IPv4/TCP/DNS/TLS).
2) Jump to the protocol page for context.
3) Use a field page when you need exact values and effects.

Each field page should link back to its protocol page and at least one topic page.

IPv4 fields

IPv4 TTL8 bits
IPv4 Flags: DF1 bit
IPv4 Identification Soon16 bits
IPv4 Header Checksum Soon16 bits

TCP fields

TCP Flags: SYN1 bit
TCP Flags: ACK Soon1 bit
TCP Window16 bits
TCP Option: MSS SoonVariable

DNS fields

DNS RCODE4 bits
DNS QTYPE Soon16 bits
DNS Transaction ID Soon16 bits
DNS Flags: RD/RA Soon1 bit

TLS fields

TLS SNIExtension
TLS Version Soon2 bytes
Cipher Suite Soon2 bytes
ALPN SoonExtension

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