# How to whitelist NULL values?

**URL:** <https://discuss.elastic.co/t/how-to-whitelist-null-values/293449>\
**Category:** Elasticsearch\
**Created:** [January 4, 2022, 1:55pm UTC](https://discuss.elastic.co/t/how-to-whitelist-null-values/293449 "2022-01-04T13:55:57Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Wooden\_tree](https://avatars.discourse-cdn.com/v4/letter/w/d2c977/32.png) [@Wooden\_tree](https://discuss.elastic.co/u/Wooden_tree)\
**Post date:** [January 4, 2022, 1:55pm UTC](https://discuss.elastic.co/t/how-to-whitelist-null-values/293449/1 "2022-01-04T13:55:57Z")

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Hello,

I’m a quite new in Elastic world and I’d like to know if it’s possible to whitelist a NULL value.

We have a rule that detects the authentications of our privileges accounts on unauthorized assets which is based on a whitelist. Unfortunately, some of events have “Workstation Name” and “Source Network Address” fields empty (a guess that dash symbol represents a NULL value in Elastic).

![1](https://us1.discourse-cdn.com/elastic/original/3X/1/2/12a37f768ba295725efa83041dd7ce0ff4ca877d.png)

These events generate an alert at each appearance because the NULL value is not whitelisted. So the question is how can it be whitelisted?

Thanks for the help!

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [February 1, 2022, 1:56pm UTC](https://discuss.elastic.co/t/how-to-whitelist-null-values/293449/2 "2022-02-01T13:56:14Z")

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