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Version: 2.10.2

DNS Users Monitor (10005, 20005)

Description

This Module reports DNS users by monitoring DNS traffic (dest_port=53). It consolidates NetFlow records over a period of time (Data Collection Interval) which all have the same combination of the following fields:

  • Source IP address
  • Destination IP address
  • Destination port number
  • Layer 3 protocol

This information is provided per NetFlow exporter.

Parameters

Parameter NameDescriptionComments
Data Collection Interval, secModule logic execution intervalmin = 30 sec, max = 600 sec, default = 60 sec
How many most active DNS requestors do you want to report?Top N (number of reported hosts)min = 0, max = 100000, default = 0 (0 indicates all hosts are reported)

Input

NetFlow v5, v9, IPFIX, Cisco ASA NSEL, Palo Alto Networks NetFlow v9, sFlow, AWS GCP VPC Flow logs, Azure NSG Flow logs.

Required NetFlow fields

Information Element (IE)IE idIE size, BDescription
IPv4
sourceIPv4Address84The IPv4 source address in the IP packet header
destinationIPv4Address124The IPv4 destination address in the IP packet header
IPv6
sourceIPv6Address2716The IPv6 source address in the IP packet header
destinationIPv6Address2816The IPv6 destination address in the IP packet header
protocolIdentifier41The value of the protocol number in the IP packet header. The protocol number identifies the IP packet payload type. Protocol numbers are defined in the IANA Protocol Numbers registry.
sourceTransportPort72The source port identifier in the transport header. For the transport protocols UDP, TCP, and SCTP, this is the source port number given in the respective header.
destinationTransportPort72The destination port identifier in the transport header. For the transport protocols UDP, TCP, and SCTP, this is the destination port number given in the respective header.

Syslog/JSON Message Fields

KeyField DescriptionComments
nfc_idMessage type identifier“nfc_id=20005”
exp_ipNetFlow exporter IP addressIPv4_address
protocolTransport Protocol (TCP = 6, UDP = 17)number
src_ipSource host IPv4 addressIPv4_address
src_ip6Source host IPv6 addressIPv6_address
dest_ipDNS server IPv4 addressIPv4_address
dest_ip6DNS server IPv6 addressIPv6_address
dest_portDestination port number53
packets_inPackets in the flownumber
bytes_inBytes in the flownumber
flow_countNumber of flowsnumber
t_intObservation time interval, msecnumber