dnstap

Collect DNS logs from a dnstap-compatible server

status: beta role: daemon delivery: best effort acknowledgements: no egress: stream state: stateless output: log
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Configuration

Example configurations 

{
  "sources": {
    "my_source_id": {
      "type": "dnstap",
      "address": "0.0.0.0:9000",
      "mode": "tcp"
    }
  }
}
[sources.my_source_id]
type = "dnstap"
address = "0.0.0.0:9000"
mode = "tcp"

sources:
  my_source_id:
    type: dnstap
    address: 0.0.0.0:9000
    mode: tcp

{
  "sources": {
    "my_source_id": {
      "type": "dnstap",
      "address": "0.0.0.0:9000",
      "max_frame_length": 102400,
      "mode": "tcp",
      "permit_origin": [
        "192.168.0.0/16"
      ],
      "port_key": "port",
      "shutdown_timeout_secs": 30,
      "socket_file_mode": 511
    }
  }
}
[sources.my_source_id]
type = "dnstap"
address = "0.0.0.0:9000"
max_frame_length = 102_400
mode = "tcp"
permit_origin = [ "192.168.0.0/16" ]
port_key = "port"
shutdown_timeout_secs = 30
socket_file_mode = 511

sources:
  my_source_id:
    type: dnstap
    address: 0.0.0.0:9000
    max_frame_length: 102400
    mode: tcp
    permit_origin:
      - 192.168.0.0/16
    port_key: port
    shutdown_timeout_secs: 30
    socket_file_mode: 511

address

required string literal

The socket address to listen for connections on, or systemd{#N} to use the Nth socket passed by systemd socket activation.

If a socket address is used, it must include a port.

Examples 
"0.0.0.0:9000"
"systemd"
"systemd#3"
Relevant when: mode = "tcp"

connection_limit

optional uint
The maximum number of TCP connections that are allowed at any given time.
Relevant when: mode = "tcp"

host_key

optional string literal

Overrides the name of the log field used to add the source path to each event.

The value is the socket path itself.

By default, the global log_schema.host_key option is used.

keepalive

optional object
TCP keepalive settings for socket-based components.

keepalive.time_secs

optional uint
The time to wait before starting to send TCP keepalive probes on an idle connection.
Relevant when: mode = "tcp"

lowercase_hostnames

optional bool
Whether to downcase all DNSTAP hostnames received for consistency
default: false

max_connection_duration_secs

optional uint

Maximum duration to keep each connection open. Connections open for longer than this duration are closed.

This is helpful for load balancing long-lived connections.

Relevant when: mode = "tcp"

max_frame_handling_tasks

optional uint
Maximum number of frames that can be processed concurrently.

max_frame_length

optional uint

Maximum DNSTAP frame length that the source accepts.

If any frame is longer than this, it is discarded.

default: 102400 (bytes)

mode

required string literal enum
The type of dnstap socket to use.
Examples 
"tcp"
"unix"
Enum options string literal
OptionDescription
tcpListen on TCP.
unixListen on a Unix domain socket

multithreaded

optional bool
Whether or not to concurrently process DNSTAP frames.

permit_origin

optional [string]
List of allowed origin IP networks. IP addresses must be in CIDR notation.
Array string literal
Examples 
[
  "192.168.0.0/16",
  "127.0.0.1/32",
  "::1/128",
  "9876:9ca3:99ab::23/128"
]
Relevant when: mode = "tcp"

port_key

optional string literal

Overrides the name of the log field used to add the peer host’s port to each event.

The value will be the peer host’s port i.e. 9000.

By default, "port" is used.

Set to "" to suppress this key.

default: port
Relevant when: mode = "tcp"

raw_data_only

optional bool

Whether or not to skip parsing or decoding of DNSTAP frames.

If set to true, frames are not parsed or decoded. The raw frame data is set as a field on the event (called rawData) and encoded as a base64 string.

receive_buffer_bytes

optional uint
The size of the receive buffer used for each connection.
Relevant when: mode = "tcp"

shutdown_timeout_secs

optional uint
The timeout before a connection is forcefully closed during shutdown.
default: 30 (seconds)
Relevant when: mode = "tcp"

socket_file_mode

optional uint

Unix file mode bits to be applied to the unix socket file as its designated file permissions.

Note: The file mode value can be specified in any numeric format supported by your configuration language, but it is most intuitive to use an octal number.

Examples 
511
492
511
Relevant when: mode = "unix"

socket_path

required string literal

Absolute path to the socket file to read DNSTAP data from.

The DNS server must be configured to send its DNSTAP data to this socket file. The socket file is created if it doesn’t already exist when the source first starts.

Relevant when: mode = "unix"

socket_receive_buffer_size

optional uint

The size, in bytes, of the receive buffer used for the socket.

This should not typically needed to be changed.

Warning

System-wide setting of maximum socket send buffer size (i.e. value of ‘/proc/sys/net/core/wmem_max’ on Linux) may need adjustment accordingly.
Relevant when: mode = "unix"

socket_send_buffer_size

optional uint

The size, in bytes, of the send buffer used for the socket.

This should not typically needed to be changed.

Warning

System-wide setting of maximum socket send buffer size (i.e. value of ‘/proc/sys/net/core/wmem_max’ on Linux) may need adjustment accordingly.
Relevant when: mode = "unix"

tls

optional object
TlsEnableableConfig for sources, adding metadata from the client certificate.

tls.alpn_protocols

optional [string]

Sets the list of supported ALPN protocols.

Declare the supported ALPN protocols, which are used during negotiation with peer. They are prioritized in the order that they are defined.

tls.ca_file

optional string literal

Absolute path to an additional CA certificate file.

The certificate must be in the DER or PEM (X.509) format. Additionally, the certificate can be provided as an inline string in PEM format.

Examples 
"/path/to/certificate_authority.crt"

tls.client_metadata_key

optional string literal
Event field for client certificate metadata.

tls.crt_file

optional string literal

Absolute path to a certificate file used to identify this server.

The certificate must be in DER, PEM (X.509), or PKCS#12 format. Additionally, the certificate can be provided as an inline string in PEM format.

If this is set, and is not a PKCS#12 archive, key_file must also be set.

Examples 
"/path/to/host_certificate.crt"

tls.enabled

optional bool

Whether or not to require TLS for incoming or outgoing connections.

When enabled and used for incoming connections, an identity certificate is also required. See tls.crt_file for more information.

tls.key_file

optional string literal

Absolute path to a private key file used to identify this server.

The key must be in DER or PEM (PKCS#8) format. Additionally, the key can be provided as an inline string in PEM format.

Examples 
"/path/to/host_certificate.key"

tls.key_pass

optional string literal

Passphrase used to unlock the encrypted key file.

This has no effect unless key_file is set.

Examples 
"${KEY_PASS_ENV_VAR}"
"PassWord1"

tls.server_name

optional string literal

Server name to use when using Server Name Indication (SNI).

Only relevant for outgoing connections.

Examples 
"www.example.com"

tls.verify_certificate

optional bool

Enables certificate verification. For components that create a server, this requires that the client connections have a valid client certificate. For components that initiate requests, this validates that the upstream has a valid certificate.

If enabled, certificates must not be expired and must be issued by a trusted issuer. This verification operates in a hierarchical manner, checking that the leaf certificate (the certificate presented by the client/server) is not only valid, but that the issuer of that certificate is also valid, and so on until the verification process reaches a root certificate.

Do NOT set this to false unless you understand the risks of not verifying the validity of certificates.

tls.verify_hostname

optional bool

Enables hostname verification.

If enabled, the hostname used to connect to the remote host must be present in the TLS certificate presented by the remote host, either as the Common Name or as an entry in the Subject Alternative Name extension.

Only relevant for outgoing connections.

Do NOT set this to false unless you understand the risks of not verifying the remote hostname.

Relevant when: mode = "tcp"

Outputs

<component_id>

Default output stream of the component. Use this component’s ID as an input to downstream transforms and sinks.

Output Data

Logs

Warning

The fields shown below will be different if log namespacing is enabled. See Log Namespacing for more details

Event

A single dnstap event.
Fields
dataType optional string literal
Dnstap event data type. Currently only ‘Message’ type is defined.
dataTypeId required uint
Numeric ID of dnstap event data type.
Examples
1
error optional string literal
Error message upon failure while parsing dnstap data.
Examples
Encountered error : Unexpected number of records in update section: 0
extraInfo optional string literal
Extra data for this event.
Examples
an arbitrary byte-string annotation
messageType optional string literal
Dnstap message type.
messageTypeId required uint
Numeric ID of dnstap message type.
Examples
6
rawData optional string literal
Raw dnstap binary data encoded in Base64. Presents only upon failures or option ‘raw_data_only’ is enabled.
Examples
ChBqYW1lcy11YnVudHUtZGV2EgtCSU5EIDkuMTYuNXKdAQgCEAEYASIEfwAAASoEfwAAATDRyAM4AFoNB2V4YW1wbGUDY29tAGCTvf76BW3evGImcmlihYQAAAEAAAABAAACaDIHZXhhbXBsZQNjb20AAAYAAcAPAAYAAQAADhAAPQtiZGRzLWRuc3RhcAAKcG9zdG1hc3RlcgJubwVlbWFpbAZwbGVhc2UAJADGPgAADhAAAAJYACeNAAAADhB4AQ==
requestData optional object
Request message data for DNS query/update.
responseAddress required string literal
The network address of the message responder.
Examples
192.0.2.18
fc00::200
responseData optional object
Response message data for DNS query/update.
responsePort optional uint
The transport port of the message responder.
Examples
60364
serverId optional string literal
DNS server identity.
Examples
ns1.example.com
serverVersion optional string literal
DNS server version.
Examples
BIND 9.16.8
socketFamily required string literal
The network protocol family of a socket. This specifies how to interpret ‘sourceAddress’/‘responseAddress’ fields.
Examples
INET
INET6
socketProtocol required string literal
The transport protocol of a socket. This specifies how to interpret ‘sourcePort’/‘responsePort’ fields.
Examples
UDP
TCP
sourceAddress required string literal
The network address of the message initiator.
Examples
192.0.2.8
fc00::100
sourcePort optional uint
The transport port of the message initiator.
Examples
52398
time required uint
The time at which the DNS message was sent or received. This is the number of time units (determined by ’timePrecision’) since the UNIX epoch. For a DNS query/update request event, it’s same as request time. For a DNS query/update response event, it’s same as response time.
Examples
1614781642516276700
timePrecision required string literal
The time precision used by field ’time'.
Examples
s
ms
us
ns
timestamp required string literal
The same time as of field “time”, but represented as an ISO 8601 date and time string (in UTC time zone).
Examples
2021-04-09T15:08:32.767098Z

Telemetry

Metrics

link

component_discarded_events_total

counter
The number of events dropped by this component.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
host optional
The hostname of the system Vector is running on.
intentional
True if the events were discarded intentionally, like a filter transform, or false if due to an error.
pid optional
The process ID of the Vector instance.

component_errors_total

counter
The total number of errors encountered by this component.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
error_type
The type of the error
host optional
The hostname of the system Vector is running on.
pid optional
The process ID of the Vector instance.
stage
The stage within the component at which the error occurred.

component_received_bytes_total

counter
The number of raw bytes accepted by this component from source origins.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
container_name optional
The name of the container from which the data originated.
file optional
The file from which the data originated.
host optional
The hostname of the system Vector is running on.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the data originated.
peer_path optional
The pathname from which the data originated.
pid optional
The process ID of the Vector instance.
pod_name optional
The name of the pod from which the data originated.
uri optional
The sanitized URI from which the data originated.

component_received_event_bytes_total

counter
The number of event bytes accepted by this component either from tagged origins like file and uri, or cumulatively from other origins.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
container_name optional
The name of the container from which the data originated.
file optional
The file from which the data originated.
host optional
The hostname of the system Vector is running on.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the data originated.
peer_path optional
The pathname from which the data originated.
pid optional
The process ID of the Vector instance.
pod_name optional
The name of the pod from which the data originated.
uri optional
The sanitized URI from which the data originated.

component_received_events_count

histogram

A histogram of the number of events passed in each internal batch in Vector’s internal topology.

Note that this is separate than sink-level batching. It is mostly useful for low level debugging performance issues in Vector due to small internal batches.

component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
container_name optional
The name of the container from which the data originated.
file optional
The file from which the data originated.
host optional
The hostname of the system Vector is running on.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the data originated.
peer_path optional
The pathname from which the data originated.
pid optional
The process ID of the Vector instance.
pod_name optional
The name of the pod from which the data originated.
uri optional
The sanitized URI from which the data originated.

component_received_events_total

counter
The number of events accepted by this component either from tagged origins like file and uri, or cumulatively from other origins.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
container_name optional
The name of the container from which the data originated.
file optional
The file from which the data originated.
host optional
The hostname of the system Vector is running on.
mode optional
The connection mode used by the component.
peer_addr optional
The IP from which the data originated.
peer_path optional
The pathname from which the data originated.
pid optional
The process ID of the Vector instance.
pod_name optional
The name of the pod from which the data originated.
uri optional
The sanitized URI from which the data originated.

component_sent_event_bytes_total

counter
The total number of event bytes emitted by this component.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
host optional
The hostname of the system Vector is running on.
output optional
The specific output of the component.
pid optional
The process ID of the Vector instance.

component_sent_events_total

counter
The total number of events emitted by this component.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
host optional
The hostname of the system Vector is running on.
output optional
The specific output of the component.
pid optional
The process ID of the Vector instance.

source_lag_time_seconds

histogram
The difference between the timestamp recorded in each event and the time when it was ingested, expressed as fractional seconds.
component_id
The Vector component ID.
component_kind
The Vector component kind.
component_type
The Vector component type.
host optional
The hostname of the system Vector is running on.
pid optional
The process ID of the Vector instance.

Examples

Dnstap events for a pair of regular DNS query and response.

Given this event...
Send a query to an authoritative BIND DNS server locally with following command:

```bash
	nslookup host.example.com localhost
```
...and this configuration...
sources:
  my_source_id:
    type: dnstap
    mode: unix
    max_frame_length: 102400
    socket_file_mode: 508
    socket_path: /run/bind/dnstap.sock
    max_frame_handling_tasks: 10000

[sources.my_source_id]
type = "dnstap"
mode = "unix"
max_frame_length = 102_400
socket_file_mode = 508
socket_path = "/run/bind/dnstap.sock"
max_frame_handling_tasks = 10_000

{
  "sources": {
    "my_source_id": {
      "type": "dnstap",
      "mode": "unix",
      "max_frame_length": 102400,
      "socket_file_mode": 508,
      "socket_path": "/run/bind/dnstap.sock",
      "max_frame_handling_tasks": 10000
    }
  }
}
...this Vector event is produced:
[{"log":{"dataType":"Message","dataTypeId":1,"messageType":"ClientQuery","messageTypeId":5,"requestData":{"fullRcode":0,"header":{"aa":false,"ad":false,"anCount":0,"arCount":0,"cd":false,"id":49653,"nsCount":0,"opcode":0,"qdCount":1,"qr":0,"ra":false,"rcode":0,"rd":true,"tc":false},"question":[{"class":"IN","domainName":"host.example.com.","questionType":"A","questionTypeId":1}],"rcodeName":"NoError","time":1614781642516276700,"timePrecision":"ns"},"responseAddress":"127.0.0.1","responsePort":0,"serverId":"ns1.example.com","serverVersion":"BIND 9.16.8","socketFamily":"INET","socketProtocol":"UDP","sourceAddress":"127.0.0.1","sourcePort":52398,"time":1614781642516276700,"timePrecision":"ns"}},{"log":{"dataType":"Message","dataTypeId":1,"messageType":"ClientResponse","messageTypeId":6,"responseAddress":"127.0.0.1","responseData":{"answers":[{"class":"IN","domainName":"host.example.com.","rData":"192.0.2.100","recordType":"A","recordTypeId":1,"ttl":3600}],"authority":[{"class":"IN","domainName":"example.com.","rData":"ns1.example.com.","recordType":"NS","recordTypeId":2,"ttl":86400}],"fullRcode":0,"header":{"aa":true,"ad":false,"anCount":1,"arCount":0,"cd":false,"id":49653,"nsCount":1,"opcode":0,"qdCount":1,"qr":1,"ra":true,"rcode":0,"rd":true,"tc":false},"question":[{"class":"IN","domainName":"host.example.com.","questionType":"A","questionTypeId":1}],"rcodeName":"NoError","time":1614781642516276700,"timePrecision":"ns"},"responsePort":0,"serverId":"ns1.example.com","serverVersion":"BIND 9.16.8","socketFamily":"INET","socketProtocol":"UDP","sourceAddress":"127.0.0.1","sourceId":"421bce7d-b4e6-b705-6057-7039628a9847","sourcePort":52398,"time":1614781642516276700,"timePrecision":"ns"}}]

Dnstap events for a pair of DNS update request and response.

Given this event...
Send a dynamic update to an authoritative BIND DNS server locally with following command:

```bash
	nsupdate <<EOF
	server localhost
	update add h1.example.com 3600 a 192.0.2.110
	send
	EOF
```
...and this configuration...
sources:
  my_source_id:
    type: dnstap
    mode: unix
    socket_file_mode: 508
    socket_path: /run/bind/dnstap.sock
    socket_receive_buffer_size: 10485760
    socket_send_buffer_size: 10485760

[sources.my_source_id]
type = "dnstap"
mode = "unix"
socket_file_mode = 508
socket_path = "/run/bind/dnstap.sock"
socket_receive_buffer_size = 10_485_760
socket_send_buffer_size = 10_485_760

{
  "sources": {
    "my_source_id": {
      "type": "dnstap",
      "mode": "unix",
      "socket_file_mode": 508,
      "socket_path": "/run/bind/dnstap.sock",
      "socket_receive_buffer_size": 10485760,
      "socket_send_buffer_size": 10485760
    }
  }
}
...this Vector event is produced:
[{"log":{"dataType":"Message","dataTypeId":1,"messageType":"UpdateQuery","messageTypeId":13,"requestData":{"fullRcode":0,"header":{"adCount":0,"id":47320,"opcode":5,"prCount":0,"qr":0,"rcode":0,"upCount":1,"zoCount":1},"rcodeName":"NoError","time":1599832089886768400,"timePrecision":"ns","update":[{"class":"IN","domainName":"h1.example.com.","rData":"192.0.2.110","recordType":"A","recordTypeId":1,"ttl":3600}],"zone":{"zClass":"IN","zName":"example.com.","zType":"SOA","zTypeId":6}},"responseAddress":"127.0.0.1","responsePort":0,"serverId":"ns1.example.com","serverVersion":"BIND 9.16.8","socketFamily":"INET","socketProtocol":"UDP","sourceAddress":"127.0.0.1","sourcePort":53141,"time":1599832089886768400,"timePrecision":"ns"}},{"log":{"dataType":"Message","dataTypeId":1,"messageType":"UpdateResponse","messageTypeId":14,"responseAddress":"127.0.0.1","responseData":{"fullRcode":0,"header":{"adCount":0,"id":47320,"opcode":5,"prCount":0,"qr":1,"rcode":0,"upCount":0,"zoCount":1},"rcodeName":"NoError","time":1599832089890768400,"timePrecision":"ns","zone":{"zClass":"IN","zName":"example.com.","zType":"SOA","zTypeId":6}},"responsePort":0,"serverId":"ns1.example.com","serverVersion":"BIND 9.16.8","socketFamily":"INET","socketProtocol":"UDP","sourceAddress":"127.0.0.1","sourcePort":53141,"time":1599832089890768400,"timePrecision":"ns"}}]

How it works

Context

By default, the dnstap source augments events with helpful context keys.

Manipulate UDS Buffer Size

The dnstap source supports configuring the UDS buffer for both receiving and sending, which may be helpful for handling DNS traffic spikes more smoothly in high-usage scenarios in which performance is of paramount concern.

To configure the send/receive buffer size for the server UDS, set the socket_receive_buffer_size and socket_send_buffer_size parameters in the component’s configuration. Here’s an example:

[sources.my_dnstap_source]
type = "dnstap"
mode = "unix"
socket_receive_buffer_size = 10_485_760
socket_send_buffer_size = 10_485_760
# Other configs

For the buffer size settings to take effect, you need to ensure that the system-wide settings for send/receive buffer sizes (i.e. the values of /proc/sys/net/core/rmem_max and /proc/sys/net/core/wmem_max on Linux) are large enough.

Server Unix Domain Socket (UDS)

The dnstap source can receive dnstap data through a Unix Domain Socket (aka UDS). The path of the UDS must be explicitly specified in the source’s configuration.

Upon startup, the dnstap source creates a new server UDS at the specified path. If the path of UDS is already in use, Vector automatically deletes it before creating a new path.

The default permissions of the UDS are determined by the current umask value. To customize it to allow the local BIND server to send dnstap data to the UDS, you can specify the desired UDS permissions (for example the file mode) explicitly in the dnstap source configuration. To set its permissions to 0774, for example, add the socket_file_mode option:

[sources.my_dnstap_source]
type = "dnstap"
mode = "unix"
socket_file_mode: 0o774
# Other configs

Using a remote BIND server

While the dnstap source can create server UDS paths only on the local machine, you can also use it with remote BIND servers by forwarding the server UDS from the machine Vector is running on to the remote BIND server (for example via SSH) once Vector starts. Make sure that the Unix domain sockets on both the local and remote machines have appropriate permissions set.

State

This component is stateless, meaning its behavior is consistent across each input.

Transport Layer Security (TLS)

Vector uses OpenSSL for TLS protocols due to OpenSSL’s maturity. You can enable and adjust TLS behavior via the tls.* options and/or via an OpenSSL configuration file. The file location defaults to /usr/local/ssl/openssl.cnf or can be specified with the OPENSSL_CONF environment variable.
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