PrefDNSRelation¶

The PrefDNSRelation in the OWASP Open Asset Model (OAM) is used to represent DNS resource records that include a preference value, such as MX records that define mail server priority for a domain.

Definition: A PrefDNSRelation captures the association between a DNS name and another DNS name or IP address, along with a numeric preference value that indicates priority. This is commonly used for records like MX, SRV, or other types where ordering or selection is influenced by a preference number.
Purpose: This relation is critical for modeling DNS-based service routing and failover configurations. For example, in an MX record, the preference indicates which mail server should be contacted first. Accurately capturing this relationship helps model infrastructure behavior during service discovery, redundancy, and load distribution.
Design Choice: PrefDNSRelation builds on the simpler BasicDNSRelation by including a structured preference attribute, while still avoiding full record verbosity (e.g., no TTLs, weights, ports, or target service names). This keeps the model lightweight but expressive enough for meaningful DNS prioritization use cases.

In summary, PrefDNSRelation extends basic DNS modeling by introducing priority-aware resolution, enabling the OAM to capture more nuanced DNS relationships where preference order matters.

PrefDNSRelation Attributes¶

Attributes	Type	Description
`label`	string	The label for the relation between two assets
`header.rr_type`	number	Specifies the type of resource within the DNS record
`header.class`	number	1, IN class (Internet), is the most commonly used
`header.ttl`	number	Specifies how long a DNS record should be cached
`preference`	number	Captures the preference or priority value for this record

PrefDNSRelation Properties¶

Property Type	Property Name	Description
`SourceProperty`	Source Plugin Name	Indicates that the specified data source discovered this PrefDNSRelation