# Creating custom runtime field which does a reverse dns lookup of another field

**URL:** <https://discuss.elastic.co/t/creating-custom-runtime-field-which-does-a-reverse-dns-lookup-of-another-field/274258>\
**Category:** Kibana\
**Created:** [May 27, 2021, 7:40pm UTC](https://discuss.elastic.co/t/creating-custom-runtime-field-which-does-a-reverse-dns-lookup-of-another-field/274258 "2021-05-27T19:40:50Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![willemdh](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/willemdh/32/16922_2.png) [@willemdh](https://discuss.elastic.co/u/willemdh)\
**Post date:** [May 27, 2021, 7:40pm UTC](https://discuss.elastic.co/t/creating-custom-runtime-field-which-does-a-reverse-dns-lookup-of-another-field/274258/1 "2021-05-27T19:40:51Z")

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Hello,

Is it possible to do a (reverse) DNS lookup in a runtime field? How would I do this?

Best regards,

Willem

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**Author:** ![tylersmalley](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tylersmalley/32/8833_2.png) [@tylersmalley](https://discuss.elastic.co/u/tylersmalley)\
**Post date:** [May 28, 2021, 3:42am UTC](https://discuss.elastic.co/t/creating-custom-runtime-field-which-does-a-reverse-dns-lookup-of-another-field/274258/2 "2021-05-28T03:42:55Z")

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You would have to augment this at ingest time. Currently the best way to do this would be using Logstash.

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**Author:** ![willemdh](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/willemdh/32/16922_2.png) [@willemdh](https://discuss.elastic.co/u/willemdh)\
**Post date:** [May 28, 2021, 5:57am UTC](https://discuss.elastic.co/t/creating-custom-runtime-field-which-does-a-reverse-dns-lookup-of-another-field/274258/3 "2021-05-28T05:57:05Z")

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@tylersmalley Yes, that's how I'm doing it now. But I was hoping runtime fields would allow dns lookups on read.. (like several other data analytics platform allow)

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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:** [June 25, 2021, 5:57am UTC](https://discuss.elastic.co/t/creating-custom-runtime-field-which-does-a-reverse-dns-lookup-of-another-field/274258/4 "2021-06-25T05:57:07Z")

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