> For the complete documentation index, see [llms.txt](https://docs.elastiflow.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.elastiflow.com/additional-resources-reference-articles/faq/config_udp_input.md).

# Configure the UDP Input

### QUESTION

How can NetObserv Flow’s flow port be changed?

### ANSWER

NetObserv Flow receives packets containing flow records using UDP. There are three configurable parameters:

| Parameter                                      | Description                                                                                                                                                    |
| ---------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| EF\_FLOW\_SERVER\_UDP\_PORT                    | The UDP port which NetObserv Flow listens to for Netflow/IPFIX/sFLOW packets                                                                                   |
| EF\_FLOW\_SERVER\_UDP\_IP                      | The IP address the UDP socket is bound to on NetObserv Flow                                                                                                    |
| EF\_FLOW\_SERVER\_UDP\_READ\_BUFFER\_MAX\_SIZE | The UDP receive buffer for the system. If this value exceeds the maximum allowed buffer size (`net.core.rmem_max` on Linux), the maximum allowed size is used. |

Refer to the [Configuration Reference](https://github.com/elastiflow/documentation/blob/main/docs/config_ref/flowcoll/input_udp/README.md) for additional details.

### REFERENCE

* [Netflow/IPFIX/sFlow (UDP) Input](https://github.com/elastiflow/documentation/blob/main/docs/config_ref/flowcoll/input_udp/README.md)


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