The option OS and Server Identity Sources is a mechanism to define the source of the data being fed to the Defense Center via the Host Input API.
For example: If you have a custom application which scans hosts on your network independently of the DC and would like for that data to modify the existing host profiles, it will be necessary to add an Identity Source on the DC. This way, your custom application will be able to successfully connect and have its data stream tagged so the source of the data is properly defined in the Host Profile.
Steps To Add Custom Identity Source
Navigate to Policies > Network Discovery > Advanced.
Click on the Pencil Icon next to OS and Server Identity Sources.
Click Add Source.
In the Type field, select Scanner or Application.
In the Timeout field, indicate the duration of time that should elapse between the addition of an identity to the network map by this source and the deletion of that identity. FireSIGHT's default timeout value is 7 days.