# Clarify :ipv4 special value in network settings

**URL:** <https://discuss.elastic.co/t/clarify-ipv4-special-value-in-network-settings/169848>\
**Category:** Elasticsearch\
**Created:** [February 25, 2019, 2:18pm UTC](https://discuss.elastic.co/t/clarify-ipv4-special-value-in-network-settings/169848 "2019-02-25T14:18:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![szabolcsf](https://avatars.discourse-cdn.com/v4/letter/s/ec9cab/32.png) [@szabolcsf](https://discuss.elastic.co/u/szabolcsf)\
**Post date:** [February 25, 2019, 2:18pm UTC](https://discuss.elastic.co/t/clarify-ipv4-special-value-in-network-settings/169848/1 "2019-02-25T14:18:06Z")

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Hi,

I'm wondering: if I specify an IPv4 address in network.host like this:  
`network.host: 172.16.20.20`

does it imply this:  
`network.host: "_private:ipv4_"`

presuming I've got a NIC called private with the IP address 172.16.20.20?

This is unclear to me from the doc: [https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-network.html#network-interface-values](https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-network.html#network-interface-values)

Also, does either of these notations have any effect if `-Djava.net.preferIPv4Stack=false` and my host has IPv6 address? I.e. do I have to set `-Djava.net.preferIPv4Stack=true` on hosts with IPv6 available to make sure either `network.host: 172.16.20.20` or `network.host: "_private:ipv4_"` have any effect?

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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:** [March 25, 2019, 2:18pm UTC](https://discuss.elastic.co/t/clarify-ipv4-special-value-in-network-settings/169848/2 "2019-03-25T14:18:14Z")

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Closed on March 25, 2019, 2:18pm UTC

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