# ES 5.2.0 in KVM - Netty Warning : Failed to find a usable hardware address from the network interfaces

**URL:** <https://discuss.elastic.co/t/es-5-2-0-in-kvm-netty-warning-failed-to-find-a-usable-hardware-address-from-the-network-interfaces/73717>\
**Category:** Elasticsearch\
**Created:** [February 2, 2017, 4:23pm UTC](https://discuss.elastic.co/t/es-5-2-0-in-kvm-netty-warning-failed-to-find-a-usable-hardware-address-from-the-network-interfaces/73717 "2017-02-02T16:23:36Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![jasontedor](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jasontedor/32/66992_2.png) [@jasontedor](https://discuss.elastic.co/u/jasontedor)\
**Post date:** [February 3, 2017, 1:56am UTC](https://discuss.elastic.co/t/es-5-2-0-in-kvm-netty-warning-failed-to-find-a-usable-hardware-address-from-the-network-interfaces/73717/3 "2017-02-03T01:56:26Z")

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> [@fciocchetti](#):
>
> Does anyone know what this is ?

It was introduced by this change in Netty: [Fix DefaultChannelId MAC address parsing bug by Scottmitch · Pull Request #6147 · netty/netty · GitHub](https://github.com/netty/netty/pull/6147/)

Your MAC address is considered locally-administered address (because it starts with 0x52 -\> the second-least significant bit is not zero) and therefore is not considered a good candidate (by Netty) for the "best" MAC address.

This is not a serious issue, these are just used to label channel IDs that appear in debug statements.

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_[View the full topic](https://discuss.elastic.co/t/es-5-2-0-in-kvm-netty-warning-failed-to-find-a-usable-hardware-address-from-the-network-interfaces/73717)._