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General Internet Engineering Task Force dns This document describes the output format used between Passive DNS query interface. The output format description includes also a common meaning per Passive DNS system.

Passive DNS is a technique described by Florian Weimer in 2005 in Passive DNS replication, F Weimer - 17th Annual FIRST Conference on Computer Security. Since then multiple Passive DNS implementations evolved over time. Users of these Passive DNS servers query a server (often via Whois [Ref: WHOIS]), parse the results and process them in other applications. There are multiple implementation of Passive DNS software. Users of passive DNS query each implementation and aggregate the results for their search. This document describes the output format of three Passive DNS Systems which are in use today and which already share a nearly identical output format. As the format and the meaning of output fields from each Passive DNS need to be consistent, we propose in this document a solution to commonly name each field along with their cor responding interpretation. The format format is following a simple key-value structure. The benefit of having a consistent Passive DNS output format is that multiple client implementations can query different servers without having to have a separate parser for each individual server. [http://code.google.com/p/passive-dns-query-tool/] currently implements multiple parsers due to a lack of standardization. The document does not describe the protocol (e.g. whois ref:TOADD) used to query the Passive DNS.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

A field is composed a key followed by a value separated by the single ':' character and a space before the value. The format is based on the initial work done by Florian Weimer and the RIPE whois format (ref:http://www.enyo.de/fw/software/dnslogger/whois.html). The ordered of the fields is not significant for the same resource type, name tuple.

This field returns the first time that the record has been seen by the passive DNS. The date is expressed in ISO 8601 and UTC.

This field returns the last time that the record has been seen by the passive DNS. The date is expressed in ISO 8601 and UTC.

This field returns the resource record type as seen by the passive DNS. The key is rr-type and the value is in the interpreted record type. If the value cannot be interpreted the decimal value is returned. The resource record type can be any values as described by IANA in the DNS parameters document in the section 'DNS Label types' (http://www.iana.org/assignments/dns-parameters).

This field returns the name of the queried resource.

Specifies how many authoritative answers were received with the set of answers (i.e. same data) over all sensors. The number of requests is expressed as a decimal value.

A x- prefixed key means that is an extension and a non-standard field defined by the implementation of the passive DNS.

This template was derived from an initial version written by Pekka Savola and contributed by him to the xml2rfc project. This document is part of a plan to make xml2rfc indispensable .

This memo includes no request to IANA. All drafts are required to have an IANA considerations section (see the update of RFC 2434 for a guide). If the draft does not require IANA to do anything, the section contains an explicit statement that this is the case (as above). If there are no requirements for IANA, the section will be removed during conversion into an RFC by the RFC Editor.

All drafts are required to have a security considerations section. See RFC 3552 for a guide.

&RFC2119; &RFC2629; &RFC3552; &I-D.narten-iana-considerations-rfc2434bis; Mad Dominators, Inc.

This becomes an Appendix.