Listens for Datagram Packets on a given port. The default behavior produces a FlowFile per datagram, however for higher throughput the Max Batch Size property may be increased to specify the number of datagrams to batch together in a single FlowFile. This processor can be restricted to listening for datagrams from a specific remote host and port by specifying the Sending Host and Sending Host Port properties, otherwise it will listen for datagrams from all hosts and ports.


ingest, udp, listen, source


In the list below, the names of required properties appear in bold. Any other properties (not in bold) are considered optional. The table also indicates any default values, and whether a property supports the Expression Language Guide.

Name Default Value Allowable Values Description
Local Network Interface The name of a local network interface to be used to restrict listening to a specific LAN.
Supports Expression Language: true
Port The port to listen on for communication.
Receive Buffer Size 65507 B The size of each buffer used to receive messages. Adjust this value appropriately based on the expected size of the incoming messages.
Max Size of Message Queue 10000 The maximum size of the internal queue used to buffer messages being transferred from the underlying channel to the processor. Setting this value higher allows more messages to be buffered in memory during surges of incoming messages, but increases the total memory used by the processor.
Max Size of Socket Buffer 1 MB The maximum size of the socket buffer that should be used. This is a suggestion to the Operating System to indicate how big the socket buffer should be. If this value is set too low, the buffer may fill up before the data can be read, and incoming data will be dropped.
Character Set UTF-8 Specifies the character set of the received data.
Max Batch Size 1 The maximum number of messages to add to a single FlowFile. If multiple messages are available, they will be concatenated along with the <Message Delimiter> up to this configured maximum number of messages
Batching Message Delimiter \n Specifies the delimiter to place between messages when multiple messages are bundled together (see <Max Batch Size> property).
Sending Host IP, or name, of a remote host. Only Datagrams from the specified Sending Host Port and this host will be accepted. Improves Performance. May be a system property or an environment variable.
Supports Expression Language: true
Sending Host Port Port being used by remote host to send Datagrams. Only Datagrams from the specified Sending Host and this port will be accepted. Improves Performance. May be a system property or an environment variable.
Supports Expression Language: true


Name Description
success Messages received successfully will be sent out this relationship.

Reads Attributes:

None specified.

Writes Attributes:

Name Description
udp.sender The sending host of the messages.
udp.port The sending port the messages were received.