We don't know your data. Ideally, your site has a data dictionary with this information, but that's rare. Consult your Splunk admin about that.
You can use the metadata command to get a list of sourcetypes or use this query.
| tstats count where index=* by index,sourcetype
then take educated guesses about which sourcetype is more likely to contain the data you seek. Search that sourcetype to verify your guess.
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If this reply helps you, Karma would be appreciated.
