Data Model
Synapse’s knowledge graph is built on a robust, extensible data model that can represent a broad range of data and relationships. The data model (and associated Analytical Model) allow both data and assertions to be represented in a structured, consistent manner. This means that instead of analysts needing to review prose reports to understand current state (and fuse those reports into still more prose to revise their assessments), analysts (and algorithms) can ask analytical questions directly of the data - and answer those questions quickly and easily.
Capturing data and analysis in a structured model abstracts away some of the subtleties and caveats that can be conveyed in prose, and finished reporting is still appropriate in many cases. But a good data model can represent enough information so that key objects, relationships, and assessments are well-defined, unambiguous, and self-evident upon examination.
This section provides background on the components of Synapse’s data model and their use.
Tip
There are various ways to examine Synapse’s data model in greater detail:
Synapse Enterprise customers or users who have requested a Synapse demo instance and have access to the Synapse UI (Optic) can use the Data Model Explorer to view Synapse’s forms and light edges and their relationships to each other. The Tag Explorer can be used to view the tags that exist in your instance of Synapse.
Data model components such as types, forms, and properties are generated as runtime nodes (“runt nodes”) when a Cortex is initialized and can be viewed as meta-objects within Synapse itself. See the Storm Reference - Model Introspection section for details.
The data model is defined in the Synapse source code. The Synapse Data Model provides a technical reference of individual types and forms, and includes our data model deprecation policy.
Data Model Objects
To work effectively with Synapse and the Storm query language, you need to understand the basic elements of the Synapse data model.
Type
A type is the definition of a data element within the Synapse data model. A type describes what the element is and enforces how it should look, including how it should be normalized, if necessary, for both storage (including indexing) and representation (display).
Synapse’s data model includes standard types such as integers and strings, but further defines a broad range of
types such as globally unique identifiers (guid
), date/time values (time
), time intervals (ival
), and
tags (syn:tag
).
Objects (nodes) may also be specialized types. For example, an IPv4 address (inet:ipv4
) is its own type.
An IPv4 address is stored as an integer, but the inet:ipv4
type has additional constraints (e.g., to ensure
that IPv4s created in Synapse only use integer values that fall within the allowable IPv4 address space). These
constraints may be defined by a Constructor that specifies how a property of that type can
be created (constructed) in Synapse.
Synapse uses Type Enforcement, Type Normalization, and Type Awareness to ensure consistency in the way data is entered, stored, and represented, and to facilitate navigation of the knowledge graph.
Type-Specific Behavior
Synapse includes optimizations for some types to improve performance and functionality. Some of these are “back end” optimizations (i.e., for indexing and storage) while some are more “front end” in terms of how users can interact with data. See Storm Reference - Type-Specific Storm Behavior for additional detail.
Form
A form is the definition of an object in the Synapse data model. A form acts as a “template” that tells you how
to create a particular object (node). While the concepts of form and node are closely related, it is useful
to maintain the distinction between the template for creating an object (a form) and an instance of a particular
object (a node). inet:fqdn
is a form; inet:fqdn = vertex.link
is a node.
All forms must have a primary property. The primary property is the name of the form and the definition of the
value to be provided for individual instances (nodes) of that form. The primary property must be defined so that it
is unique across all possible instances of that form. For example, FQDNs are unique, based on the way they are defined
and registered (two different organizations cannot both register the FQDN vertex.link
). So the primary property
value of an inet:fqdn
is simply the FQDN itself.
All properties in Synapse must have a defined type; in many cases, a form is also its own type (for example, the form
inet:fqdn
has a type of inet:fqdn
).
Forms may have secondary properties that record additional information about the form or further describe it. Secondary properties are form-specific. In most cases, secondary properties are explicitly defined for each form. If similar forms should share a subset of common properties, the properties may be defined as an interface that is inherited by those forms.
Synapse also supports a set of universal secondary properties (universal properties) that are valid for all forms.
Extended properties may be added to forms to store specialized or use case-specific data related to the form.
Form Namespace
Synapse uses a structured namespace for forms. Each form name consists of at least two elements separated by a
colon ( :
). For example:
file:bytes
inet:fqdn
ou:org
risk:threat
The first element in the namespace represents a rough “category” for the form (i.e., inet
for Internet-related
objects). The Synapse data model is broad and extensible. The ability to group portions of the data model into
related categories makes a large model easier to manage, and also allows Synapse users to focus on those portions
of the model most relevant to them.
The second and / or subsequent elements in the form name define the specific “subcategory” or “thing” within the
form’s primary category (e.g., inet:fqdn
represents a fully qualified domain name (FQDN) within the “Internet”
(inet
) category.
Properties have a namespace that extends the form namespace (form names are also primary properties). See Property and Property Namespace below for additional detail.
Extended Form
Synapse users can add their own extended forms to the data model using the $lib.model.ext libraries.
Note
We strongly encourage Synapse users who are considering extending the data model by creating custom forms to reach out to The Vertex Project first - you can readily contact us through our Slack channel. If there are gaps or missing elements in the data model, we would prefer to expand Synapse’s data model for all users vs. individual users making numerous one-off customizations. If an extended form is appropriate for the use case, we can also offer feedback to help ensure the form’s design is consistent with best practices.
Interface
An interface defines a set of secondary properties that should be present on a particular subset of forms. Instead of explicitly defining each secondary property on each form, the forms can be defined as inheriting a particular interface and its associated properties. This both simplifies and ensures consistency in the data model.
For example, Synapse uses several forms to represent activity occurring on a host, such as a file being added
(it:exec:file:add
) or a process being executed (it:exec:proc
). These forms represent similar operations,
so they all share a subset of secondary properties such as the time of execution (:time
) or the file
(:exe
) or process (:proc
) responsible for the activity. These properties are defined as an
it:host:activity
interface which is then declared / inherited for each form.
Interfaces can be inherited by other interfaces. For example, the inet:proto:request
interface, which
represents a client (host) requesting a network connection, inherits the it:host:activity
interface.
Interfaces can be used in Storm lift, filter, and pivot operations to make it easier to work with nodes of all forms that share the interface (vs. specifying each kind of node separately). See the appropriate sections of the Storm Reference for details.
Node
A node is a unique object within Synapse; they are specific instances of generic forms. Every node consists of:
A primary property, represented by the form of the node plus its value (
<form> = <valu>
). All primary properties must be unique for a given form; the uniqueness of the<form> = <valu>
pair ensures there can be only one node in Synapse that represents the domain woot.com (inet:fqdn = woot.com
). Because this unique pair “defines” the node, the comma-separated form / value combination (<form>,<valu>
) is also known as the node’s Ndef (short for “node definition”).One or more universal properties and an associated property value. As the name implies, universal properties apply to all nodes.
Optional secondary properties. Similar to primary properties, secondary properties consist of a property name (of a specific type) and the property’s value (
<prop> = <pval>
).Optional tags. A tag acts as a label with a particular meaning that can be applied to a node to provide context.
Optional extended properties and their associated values.
Node Example
The Storm query below lifts and displays the node for the domain www.google.com
:
storm> inet:fqdn=www.google.com
inet:fqdn=www.google.com
:domain = google.com
:host = www
:issuffix = false
:iszone = false
:zone = google.com
:_virustotal:reputation = 497
:_virustotal:votes:harmless = 318
:_virustotal:votes:malicious = 53
.created = 2024/11/20 18:08:28.158
#rep.moz.500
In the output above:
inet:fqdn = www.google.com
is the primary property (<form> = <valu>
)..created
is a universal property showing when the node was added to the Cortex.:domain
,:host
, etc. are form-specific secondary properties with their associated values (<prop> = <pval>
). For readability, secondary properties (including universal properties and extended properties) are displayed as relative properties within the namespace of the form’s primary property (e.g.,:domain
as opposed toinet:fqdn:domain
).The various
:_virustotal:*
properties are extended properties added to the data model by the Synapse-VirusTotal Power-Up to represent specialized data provided by VirusTotal.#rep.moz.500
is a tag indicating thatwww.google.com
has been reported by web analytics company Moz as one of their top 500 most popular websites.
See Kinds of Nodes below for additional detail on how nodes are used to represent various objects in Synapse.
Property
Properties are the individual elements that define a form or (along with their values) that comprise a node. All properties in Synapse must have a defined type.
Primary Property
Every form consists of (at minimum) a primary property: the name of the form and the definition of the value to be provided for individual instances (nodes) of that form. All forms must be designed so that their primary property value is unique across all instances (nodes) of that form.
This uniqueness is straightforward for simple objects such as FQDNs or email addresses. Ensuring “uniqueness” for more complex nodes (such as those representing a Relationship or an Event) can be more challenging; these forms are often GUID forms.
Because a primary property uniquely defines a node, it cannot be modified once the node is created. To “change” a node’s primary property value you must delete and re-create the node.
Secondary Property
A form can include optional secondary properties that provide additional detail about the form. Secondary
properties are specific to a given form and further describe that form. A node may include secondary properties
with their associated values (<prop> = <pval>
).
Some secondary properties are based on (derived from) a node’s primary property value. For example, an email
address (inet:email
) has secondary properties for both the associated FQDN (inet:email:fqdn
) and username
(inet:email:user
). When you create the node inet:email=info@vertex.link
, Synapse automatically sets the
associated secondary property values. Any secondary properties derived from a node’s primary property are read-only
(just like the primary property they are based on) and cannot be changed once set.
Any secondary properties not based on a node’s primary property are optional. Their values can be set if
the data is available and relevant to your use case; otherwise they can remain unset. For example, an IPv4 node
(inet:ipv4
) has an optional secondary property for its associated Autonomous System (AS) number (inet:ipv4:asn
).
All optional secondary property values can be set, modified, or removed as needed.
Universal Property
Synapse defines a subset of secondary properties as universal properties that are applicable to all forms:
.created
, which is set automatically by Synapse for all nodes and whose value is the date/time that the node was created within that instance of Synapse (Cortex)..seen
, which is optional for all nodes and whose value is a time interval (minimum or “first seen” and maximum or “last seen”) during which the node was observed, existed, or was valid.
Extended Property
Synapse supports the addition of specialized (“extended”) properties outside of Synapse’s baseline data model. Extended properties may be used to represent specialized data that is relevant for specific use cases and can be added using the $lib.model.ext libraries.
For example, third-party vendors that provide threat intelligence or cybersecurity data may include vendor assessments, such as “risk” or “reputation” scores. These values may only be “interesting” to security researchers, and are provided by a very specific data source. Instead of adding these specialized values to the baseline data model, extended properties can be added as needed to accommodate specialized needs.
Extended properties must start with an underscore ( :_<extended_property>
) to avoid name collisions
with baseline data model properties (current or future). In addition, we recommend using the name of the
vendor or data source (if appropriate) as the first element in the property namespace (e.g.,
:_virustotal:reputation
).
Note
We strongly encourage Synapse users who are considering extending the data model by creating custom properties to reach out to The Vertex Project first - you can readily contact us through our Slack channel. If there are gaps or missing elements in the data model, we would prefer to expand Synapse’s data model for all users vs. individual users making numerous one-off customizations. If an extended property is appropriate for the use case, we can also offer feedback to help ensure the property’s design is consistent with best practices.
Property Namespace
Properties extend the Form Namespace. Form names are primary properties, and consist of at least
two elements separated by a colon ( :
).
Secondary properties exist within the namespace of their primary property (form). Secondary properties are preceded by a colon (
:
) and use the colon to separate additional namespace elements, if needed.Universal properties are preceded by a period (
.
) to distinguish them from form-specific secondary properties.Extended properties are preceded by a colon and an underscore (
:_
).
For example, the secondary (both universal and form-specific) properties of inet:fqdn
include:
inet:fqdn.created
(universal property)inet:fqdn:zone
(secondary property)
The VirusTotal Power-Up adds extended properties to various forms, including inet:fqdn
:
inet:fqdn:_virustotal:reputation
Secondary properties (including extended and universal properties) also make up a relative namespace (set of
relative properties) with respect to their primary property (form). The Storm query language allows (or
in some cases, requires) you to reference a property using its relative property name (i.e., :zone
vs.
inet:fqdn:zone
).
Relative properties are also used for display purposes within Synapse for visual clarity (see the Node Example above).
Secondary properties (including extended properties) may have their own namespace. Both primary and secondary properties use colons to separate elements of the property name. However, not all separators represent property “boundaries”; some act more as “sub-namespace” separators.
For example file:bytes
is a primary property / form. A file:bytes
form may include
secondary properties such as :mime:pe:imphash
and :mime:pe:compiled
. In these examples, :mime
and :mime:pe
are not secondary properties, but sub-namespaces for individual MIME data types and the
“PE executable” data type specifically.
Tag
Tags are annotations applied to nodes. They can be thought of as labels that provide context to the data represented by the node.
Broadly speaking, within Synapse:
Nodes represent things: objects, relationships, or events. In other words, nodes typically represent observables that are verifiable and largely unchanging.
Tags typically represent assessments: observations that could change if the data or the analysis of the data changes.
For example:
An Internet domain is an “observable thing” - a domain exists, was registered through a domain registrar, and can be created as a node such as
inet:fqdn = woot.com
.Whether a domain has been sinkholed is an assessment. A researcher may need to evaluate data related to that domain (such as domain registration records or current and past IP resolutions) to decide whether the domain appears to be sinkholed. This assessment can be represented by applying a tag such as
cno.infra.dns.sink.holed
to theinet:fqdn = woot.com
node.
Tags can include Tag Timestamps and support the addition of Tag Properties.
Tags are unique within the Synapse model because tags are both nodes and labels applied to nodes. The tag
cno.infra.dns.sink.holed
can be applied to another node; but the tag itself also exists as the node
syn:tag = cno.infra.dns.sink.holed
. This difference is illustrated in the example below.
Tip
Synapse does not have any pre-defined tags. Users are free to create tags that are meaningful for their analysis. See Analytical Model for more detail.
Tag Example
The Storm query below displays the node for the tag cno.infra.dns.sink.holed
:
storm> syn:tag=cno.infra.dns.sink.holed
syn:tag=cno.infra.dns.sink.holed
:base = holed
:depth = 4
:doc = A domain (zone) that has been sinkholed.
:title = Sinkholed domain
:up = cno.infra.dns.sink
.created = 2024/11/20 18:08:28.235
The Storm query below displays the tag cno.infra.dns.sink.holed
applied to the node inet:fqdn = hugesoft.org
:
storm> inet:fqdn=hugesoft.org
inet:fqdn=hugesoft.org
:domain = org
:host = hugesoft
:issuffix = false
:iszone = true
:zone = hugesoft.org
.created = 2024/11/20 18:08:28.258
#cno.infra.dns.sink.holed
Note that a tag applied to a node uses the “hashtag” symbol ( #
). This is a visual cue to distinguish tags
on a node from the node’s secondary properties. The symbol is also used within the Storm query language syntax to
reference a tag as opposed to a syn:tag
node.
Lightweight (Light) Edge
Lightweight (light) edges are used in Synapse to provide greater flexibility and improved performance when representing
certain types of relationships. A light edge is similar to an edge in a traditional directed graph; each light edge
links exactly two nodes (n1
and n2
), and consists of:
A direction. Light edge relationships only “make sense” in one direction, given the forms that they link. For example, an article can reference an indicator such as an MD5 hash, but an MD5 hash does not “reference” an article.
A “verb” that represents the relationship (e.g.,
refs
for “references” in the example above).
Light edges do not have properties, and you cannot apply tags to light edges - hence the “light” in light edge.
Light edges are used for performance and flexibility in certain use cases. For example:
When the only information you need to record about a relationship is that it exists (that is, no properties are required to further “describe” the relationship). An example is
meta:ruleset -(contains)> meta:rule
.When the objects (nodes) involved in the relationship may vary. That is, either the
n1
orn2
node (or both) may be any kind of node, depending on the context of the relationship. Examples includemeta:source -(seen)> *
(where a data source may “see”, observe, or provide data on anyn2
object) and* -(refs)> *
(where a variety ofn1
nodes may “reference” or contain a reference to anyn2
node).When the objects (nodes) to be linked do not share any properties in common (i.e., that could allow the nodes to be implicity linked via a shared property value / pivot relationship).
Synapse’s source code includes some pre-defined light edges that represent The Vertex Project’s conventions. While we recommend the use of these conventions, we do not enforce their use. Synapse users are free to create / define their own light edges and use them as they see fit. (Note that Synapse Power-Ups provided by The Vertex Project will create light edges according to our conventions when ingesting data.)
Tip
Light edges should not be used as a convenience to short-circuit proper data modeling using forms. Using forms and nodes (combined with Synapse’s strong typing, type enforcement, and type awareness) are key to the powerful analysis and performance capabilities of a Synapse hypergraph.
Kinds of Forms
Synapse forms can be broadly grouped based on how their primary properties (<form> = <valu>
) are formed.
Recall that primary properties must be defined so that they are unique for all possible instances of that form.
Simple Form
A simple form refers to a form whose primary property is a single value. Simple forms are commonly used to represent an Object and are the most readily understood from a modeling perspective. The “object itself” is unique by definition, so the form’s primary property value is the object. Examples of simple forms include FQDNs, IP addresses (IPv4 or IPv6), hashes, and so on.
Composite (Comp) Form
A composite (comp) form is one where the primary property is a comma-separated list of two or more elements. While no single element makes the form unique, a set of elements may be sufficiently unique to define the form. Comp forms are often (though not universally) used to represent a Relationship.
Fused DNS A records are an example of a comp form. A DNS A record can be uniquely defined by the combination
of the domain (inet:fqdn
) and the IP address (inet:ipv4
) in the A record. In Synapse, an inet:dns:a
form represents the knowledge that a given domain resolved to a specific IP at some time, or within a time window.
(The universal .seen
property captures “when” (first observed / last observed) the resolution took place.)
Guid Form
A guid (Globally Unique Identifier) form is uniquely defined by a machine-generated 128-bit number. Guids account for cases where it is impossible to uniquely define a thing based on a property or set of properties. Guids are also useful for cases where the amount of data available to create a particular object (node) may vary greatly - that is, not all properties or details are available from all data sources. A guid form gives you the flexibility (through secondary properties) to capture as much (or as little) data as is available to you.
A guid form can be considered a special case of a simple form where the form’s value is a <guid>
.
Forms that represent one-time events are often guid forms. Examples include host execution activity (such as
it:exec:file:add
nodes) or network activity (such as inet:dns:request
nodes). Guid forms are also used
to represent entities such as people (ps:person
) or organizations (ou:org
).
Note
Guid values can be arbitrary (generated ad-hoc by Synapse) or predictable / deconflictable (generated based on a specific set of inputs). See the guid section of Storm Reference - Type-Specific Storm Behavior for a more detailed discussion of this concept.
Edge (Digraph) Form
An edge (digraph) form is a specialized composite form where the set of values for the primary property
includes at least one ndef (“node definition, or <form>,<valu>
pair). An edge form is a specialized
relationship form that can be used when one or both of the forms to be linked could be an arbitrary (i.e., any)
form. For example, a meta:seen
node (now replaced by a seen
light edge) was previously used to link a
meta:source
(using the node’s guid value) to an arbitrary node that was “seen” by the source (such as the
domain “woot.com”, using the ndef value inet:fqdn, woot.com
).
Edge forms predate the introduction of light edges to the Synapse data model; light edges were added in order to address some of the performance overhead incurred by edge forms (i.e., it is easier and faster to create a light edge for simple relationships vs. creating an entire node simply to link two other nodes).
Edge forms may be appropriate for particular use cases, but light edges are generally preferred where possible.
Generic Form
The Synapse data model includes a number of “generic” forms that can be used to represent metadata and / or arbitrary data.
Synapse’s data model can be expanded as needed, so ideally all data in Synapse would be represented using an appropriate form. However, designing a new form may require discussion, subject matter expertise, and testing against “real world” data, as well as time to implement the changes. Analysts may have a need to capture data “in the moment” without waiting for model updates. Alternatively, some data may be “one off” information that needs to be represented, but does not necessarily require its own form for a limited or unique use case.
In the above cases, generic forms may be used to capture data where a more specific form does not exist. Generic
forms reside in two primary parts of the data model: meta:*
forms and graph:*
forms.
The meta:rule
form is an example of a generic form. Synapse includes more specific forms to represent common
detection logic such as antivirus (it:av:sig
and it:av:filehit
) or YARA rules (it:app:yara:rule
and
it:app:yara:match
). Other technologies or organizations may have their own specific (and often “black box”)
detection logic.
A meta:rule
form can represent an arbitrary detection rule, with a -(matches)>
light edge used to link the
rule to the “thing” (file, network traffic, etc.) that the rule fired on.
Kinds of Nodes
Nodes represent standard objects (“nouns”) such as IP addresses, files, people, conferences, or airplanes. They can also represent more abstract objects such as industries, risks, attacks, or goals. However, in Synapse nodes can also represent relationships or specific time-based events. You can think of a node generically as a “thing” - most “things” you want to model within Synapse are nodes.
Broadly speaking, nodes can be thought of in terms of some generic categories:
Object
Nodes can represent atomic objects or entities, whether real or abstract. Entities are often (though not always)
represented as a Simple Form. An email address (inet:email
) is a basic example of an entity-type node /
simple form:
storm> inet:[email protected]
inet:[email protected]
:fqdn = yandex.ru
:user = kilkys
.created = 2024/11/20 18:08:28.325
Relationship
Nodes can represent specific relationships among entities. Examples include a domain resolving to an IPv4 address, a malware dropper containing or extracting another file, a company being a subsidiary of another business, or a person being a member of a group.
Relationship nodes are often represented as a Composite (Comp) Form. Comp forms have a primary property consisting
of a comma-separated list of two or more values that uniquely define the relationship. A DNS A record (inet:dns:a
)
is a basic example of a relationship node:
storm> inet:dns:a=(google.com,172.217.9.142)
inet:dns:a=('google.com', '172.217.9.142')
:fqdn = google.com
:ipv4 = 172.217.9.142
.created = 2024/11/20 18:08:28.370
Event
Nodes can represent individual time-based occurrences. The term event implies that an entity existed or a relationship occurred at a specific point in time. Events represent the combination of a node and a timestamp for when the node was observed. Examples of event forms include an individual login to an account, a specific DNS query, or a domain registration (whois) record captured on a specific date.
The structure of an event node may vary depending on the specific event being modeled. A “simple” event
may be represented as a Composite (Comp) Form that combines an entity and a timestamp; for example, a domain whois
record (inet:whois:rec
) consists of the whois record and the time that record was observed or retrieved.
Other more complex events are represented as a Guid Form with the timestamp as one of several secondary
properties on the form. A specific, individual DNS query (inet:dns:request
) is an example of an event node:
storm> inet:dns:request=00000a17dbe261d10ce6ed514872bd37
inet:dns:request=00000a17dbe261d10ce6ed514872bd37
:query = ('tcp://199.68.196.162', 'download.applemusic.itemdb.com', '1')
:query:name = download.applemusic.itemdb.com
:query:name:fqdn = download.applemusic.itemdb.com
:query:type = 1
:reply:code = NOERROR
:server = tcp://178.62.239.55
:time = 2018/09/30 16:01:27.506
.created = 2024/11/20 18:08:28.416
Instance Knowledge vs. Fused Knowledge
For some types of data, event nodes and relationship nodes can encode similar information but represent the difference between instance knowledge and fused knowledge.
Event forms represent the specific point-in-time existence of an entity or occurrence of a relationship - an instance of that knowledge.
Relationship forms can leverage the universal
.seen
property to set “first observed” and “last observed” times during which an entity existed or a relationship was true. This date range can be viewed as fused knowledge - knowledge that summarizes or “fuses” the data from many individual observations (instances) of the node over time.
Instance knowledge and fused knowledge represent differences in data granularity. Whether to create an event node or a relationship node (or both) depends on how much detail is required for your analysis. This consideration often applies to relationships that change over time, particularly those that may change frequently.
DNS records are a good example of these differences. The IP address that a domain resolves to may change infrequently (e.g., for a website hosted on a stable server) or may change quite often (e.g., where the IP is dynamically assigned or where load balancing is used).
One option to represent and track DNS A records is to create individual events every time you check the domain’s
current resolution (e.g., inet:dns:request
and inet:dns:answer
forms). This represents a very high degree
of granularity as the nodes will record the exact time a domain resolved to a given IP. The nodes can also capture
additional detail such as the querying client, the responding server, the response code, and so on. However, the
number of such nodes could readily reach into the hundreds of millions if you create nodes for every resolution
of every domain you want to track.
On the other hand, it may be sufficient to know that a domain resolved to an IP address during a given period
of time – a “first observed” and “last observed” (.seen
) range. A single inet:dns:a
node can be created
to show that domain woot.com
resolved to IP address 1.2.3.4
, where the earliest observed resolution was
2014/08/06 at 13:56 and the most recently observed resolution was 2018/05/29 at 7:32. These timestamps can be
extended (earlier or later) if additional data changes our observation boundaries.
This second approach loses some granularity:
The domain is not guaranteed to have resolved to that IP continuously throughout the entire time period.
Given only this node, we don’t know exactly when the domain resolved to the IP address during that time period, except for the earliest and most recent observations.
However, this fused knowledge may be sufficient for our needs and may be preferable to creating thousands of nodes for individual DNS resolutions.
Of course, a hybrid approach is also possible, where most DNS A record data is recorded in fused inet:dns:a
nodes but it is also possible to record high-resolution, point-in-time inet:dns:request
and inet:dns:answer
nodes when needed.