header information
163551·updated Aug 30, 2026The structured metadata carried in the leading section of a network packet or message, as distinguished from the payload or body, comprising fields such as source and destination addresses, port numbers, and protocol type. It includes attributes such as "source and destination IP address(s), source and destination port(s), and protocol type(s)" — the routing and control fields that describe where a transmission comes from, where it is going, and how it is to be handled. In security enforcement, boundary protection devices use it to "provide a packet-filtering capability based on header information" as a first-pass control mechanism, distinct from deeper content-based inspection of the payload. It represents a shallower inspection surface than full stateful or content analysis, which is why Access Control Lists that "filter based on header information" are considered less capable than stateful inspection.
Source
, provide a packet-filtering capability based on header information, or provide a message-filtering capability based on message content (e.g., implementing key word searches or using document characteristics). Organizations also consider the trustworthiness of filtering and inspection mechanisms (i.e., hardware, firmware, and software components) that are critical tothe sentence this term was read in
generalized from a web lookup of the quoted expression at proposal time Verdict: compositional.
- High resolution access control
- Network access control system and method using adaptive proxies
- Framework Mapping: Cisco Firewalls + NIST CSF 2.0 - Cisco
- Header Information definition
A definition generalized from search results is a draft to react to, not provenance. Confirm it against an authority document before this term is verified.
A web lookup ran when this term was proposed
The metadata fields carried in the structured prefix of a network packet or protocol message — such as source and destination addresses, port numbers, protocol identifiers, and routing directives — as distinct from the payload or body of that message. A packet consists of a header and a payload; the header contains parameters including source and destination addresses, port numbers, and protocol identifiers. Security and compliance controls use these fields as the primary decision surface for traffic enforcement: firewalls filter packets by examining header information separately from content information, while deep packet inspection extends analysis beyond header information into the contents of network traffic. The term applies across protocol layers and data formats — network packets, email messages, HTTP responses, and other structured data units all carry analogous header fields — and authority documents such as NIST SP 800-53 use it to distinguish the lighter-weight, faster class of filtering decisions (made on routing and addressing metadata alone) from content-based inspection. In the context of electronic mail, for example, header information means "the source, destination, and routing information attached to an electronic mail message, including the originating domain name and originating electronic mail address."
Advisory only. A term this product ships is defined by an authority document, not by a search result.
Proposed during multiword review of this document in the CKI mapping queue.
Attested in
Classifications
Entity Type
Sensitivity
Information Class
Variants
- plural
- header informations
- possessive
- header information's
- pluralpossessive
- header informations'
Framework definitions
- §1 · attested_usage_reviewer_confirmed
- No definition is given in NIST SP 800-171r3. The term is attested in use at 1 citation in that document; a definition is pending curation.Increment 2: attested in 800-171r3 without a glossary definition.
- §1 · web_lookup_draft
- The structured metadata carried in the leading section of a network packet or message, as distinguished from the payload or body, comprising fields such as source and destination addresses, port numbers, and protocol type. It includes attributes such as "source and destination IP address(s), source and destination port(s), and protocol type(s)" — the routing and control fields that describe where a transmission comes from, where it is going, and how it is to be handled. In security enforcement, boundary protection devices use it to "provide a packet-filtering capability based on header information" as a first-pass control mechanism, distinct from deeper content-based inspection of the payload. It represents a shallower inspection surface than full stateful or content analysis, which is why Access Control Lists that "filter based on header information" are considered less capable than stateful inspection.DR-088 backfill from the noun definition column
- §1 · web_lookup_draft
- The metadata fields carried in the structured prefix of a network packet or protocol message — such as source and destination addresses, port numbers, protocol identifiers, and routing directives — as distinct from the payload or body of that message. A packet consists of a header and a payload; the header contains parameters including source and destination addresses, port numbers, and protocol identifiers. Security and compliance controls use these fields as the primary decision surface for traffic enforcement: firewalls filter packets by examining header information separately from content information, while deep packet inspection extends analysis beyond header information into the contents of network traffic. The term applies across protocol layers and data formats — network packets, email messages, HTTP responses, and other structured data units all carry analogous header fields — and authority documents such as NIST SP 800-53 use it to distinguish the lighter-weight, faster class of filtering decisions (made on routing and addressing metadata alone) from content-based inspection. In the context of electronic mail, for example, header information means "the source, destination, and routing information attached to an electronic mail message, including the originating domain name and originating electronic mail address."Drafted by the propose-term web lookup (PD-018); a curator confirms or replaces it.