# Logstash and permiscious mode - no data?

**URL:** <https://discuss.elastic.co/t/logstash-and-permiscious-mode-no-data/225831>\
**Category:** Logstash\
**Created:** [March 31, 2020, 10:06am UTC](https://discuss.elastic.co/t/logstash-and-permiscious-mode-no-data/225831 "2020-03-31T10:06:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Rysiu](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/rysiu/32/61919_2.png) [@Rysiu](https://discuss.elastic.co/u/Rysiu)\
**Post date:** [March 31, 2020, 10:06am UTC](https://discuss.elastic.co/t/logstash-and-permiscious-mode-no-data/225831/1 "2020-03-31T10:06:45Z")

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Hi,

I have a problem.  
The problem is partly described on: [Using logstash to listen on mirrored ports (similar to Beats) · Issue #9948 · elastic/logstash · GitHub](https://github.com/elastic/logstash/issues/9948)

Logstash does not want to read the data sent in permiscious mode.

On the same system, tcpdump returns information about the data being sent to a specific udp port (say UDP/2002) to that system.

> user@HOSTNAME:$ sudo tcpdump -i ens192 port 2002 -c 5  
> 07:59:40.158066 IP 192.168.22.44.38388 \> HOSTNAME.2002: UDP length 1415  
> ...

Logstash has a standard configuration.

The pipeline has an input:

```
input {
  udp {
    port => 2002
  }
}

```

In Logstash log/status there is information that Logstash is listening on a given port (example UDP/2002).

However, Logstash does not actually read any data.

I can specify the listening on a specific IP address from the interface (in Logstash pipeline - input/host) but this does not solve the problem.

What could be the problem?

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [April 28, 2020, 10:06am UTC](https://discuss.elastic.co/t/logstash-and-permiscious-mode-no-data/225831/2 "2020-04-28T10:06:47Z")

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