# Host not recognized after server reboot

**URL:** <https://community.dynatrace.com/t/host-not-recognized-after-server-reboot/35149>\
**Category:** Dynatrace Managed\
**Tags:** dynatrace-managed, oneagent\
**Created:** [May 16, 2022, 7:58am UTC](https://community.dynatrace.com/t/host-not-recognized-after-server-reboot/35149 "2022-05-16T07:58:36Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![stephane\_kies](https://avatars.discourse-cdn.com/v4/letter/s/a4c791/32.png) [@stephane\_kies](https://community.dynatrace.com/u/stephane_kies)\
**Post date:** [May 16, 2022, 7:58am UTC](https://community.dynatrace.com/t/host-not-recognized-after-server-reboot/35149/1 "2022-05-16T07:58:36Z")

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We had a maintenance and we have restarted several servers, after restart they were recognized as new host by Dynatrace.

How is it possible, it is very annoying as we have tags and specific alert for this host.

Is it possible to force the host unique identification to ensure that this kind of issue does not happen anymore.

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**Author:** ![pahofmann](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/pahofmann/32/17076_2.png) [@pahofmann](https://community.dynatrace.com/u/pahofmann)\
**Post date:** [May 16, 2022, 8:02am UTC](https://community.dynatrace.com/t/host-not-recognized-after-server-reboot/35149/2 "2022-05-16T08:02:29Z")

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By default dynatrace determines the host identifier automatically and saves it to a file on the host. If that file is not deleted, the host should be recognized as the same one after a reboot, or even reinstallation of the OneAgent.

You could also change the way [dynatrace determines the host id.](https://www.dynatrace.com/news/blog/tackle-complex-dynatrace-managed-environments-with-declarative-host-identifiers-that-ensure-continuity-in-reporting-and-alerting/#:~:text=In%20automatic%20mode%2C%20which%20is,an%20environment%20change%20is%20detected.)

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**Author:** ![stephane\_kies](https://avatars.discourse-cdn.com/v4/letter/s/a4c791/32.png) [@stephane\_kies](https://community.dynatrace.com/u/stephane_kies)\
**Post date:** [May 16, 2022, 8:36am UTC](https://community.dynatrace.com/t/host-not-recognized-after-server-reboot/35149/3 "2022-05-16T08:36:18Z")

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Thank you, I just checked and the file ruxithost.id has been updated after the restart, I do understand that it can be cause by environment change or clone as it is a VM.

We will reinstall the agent in deterministic mode.

There is not a possibility to activate this option afterwards, we need absolutely to reinstall it ?

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**Author:** ![pahofmann](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/pahofmann/32/17076_2.png) [@pahofmann](https://community.dynatrace.com/u/pahofmann)\
**Post date:** [May 16, 2022, 8:45am UTC](https://community.dynatrace.com/t/host-not-recognized-after-server-reboot/35149/4 "2022-05-16T08:45:48Z")

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It can also be set via the [oneagentctl command-line utility.](https://www.dynatrace.com/support/help/shortlink/oneagentctl#host-id)