SNMP engineid generation

We are trying to use Ansible to template snmp, we have rebuilt one of our firewalls, and the existing one monitoring is working , the new one doesn’t using the same ansible.

The main differences between the config is one has an set service snmp v3 engineid not sure how this was generated can this id be anything? is there a special format it needs to be in?

Thanks

Engineid is a string of 10-64 characters in hexadecimal notation. The value cannot be all 0s or Fs. you can refer on the engineid format guideline from this link. RFC 5343 - Simple Network Management Protocol (SNMP) Context EngineID Discovery
You can try the MAC Address format scheme.