# Can't register Gateway - EUI is still in use

**URL:** <https://www.thethingsnetwork.org/forum/t/cant-register-gateway-eui-is-still-in-use/8952>\
**Category:** Gateways\
**Created:** [August 14, 2017, 11:16am UTC](https://www.thethingsnetwork.org/forum/t/cant-register-gateway-eui-is-still-in-use/8952 "2017-08-14T11:16:22Z")\
**Posts on this page:** 1\
**Showing post:** 22

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**Author:** ![arjanvanb](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/arjanvanb/32/46626_2.png) [@arjanvanb](https://www.thethingsnetwork.org/forum/u/arjanvanb)\
**Post date:** [September 1, 2018, 10:15am UTC](https://www.thethingsnetwork.org/forum/t/cant-register-gateway-eui-is-still-in-use/8952/22 "2018-09-01T10:15:52Z")

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> [@IoT\_Marco](#):
>
> change your MAC address

Though quite commonly used indeed, there is [no longer](https://www.thethingsnetwork.org/forum/t/deveui-for-non-hardware-assigned-values/2093/30) an officially supported way to convert an 48 bits MAC-address into an official EUI64. Also, the new MAC-address could already be in use, or belong to a future gateway, especially when based on the same hardware and when only making minor changes to the unique factory MAC-address.

While the chances for collisions within TTN might be very low, it might also be easier to use an officially supported [random EUI64](https://www.thethingsnetwork.org/forum/t/deveui-for-non-hardware-assigned-values/2093/23) instead, and change the gateway’s code (or configuration?) to use that value.

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