Hi. "/opt/splunk/share/GeoLite2-City.mmdb" is used by iplocation command; however, this file is outdated. I can manually download the file from here, but does Splunk have a built-in function can be used to update the database file automatically? Thanks.
Here is an option
https://github.com/georgestarcher/TA-geoip
No there is not automatic update method.
Usually the database get's updated when you upgrade splunk with the version that is shipped with it.
You can manually upgrade the database if you have a more recent copy, or have a paid version of the database.