im using splunk free version, but still the license details , says it expires on
License expiration Nov 21, 2011 9:00:05 AM
what happens after this date?
It seems to be a web gui "bug". Your license can expire, the expiration is based on Enterprise Trial expiration time, Splunk Free will works with any problem (look in Manager -> Licensing -> All license details, it'll expired on 2038).
I've converted the license to a free one, but I still see an expiration's time.
So I'll try to manually configure server.conf, and it's correct, but actually I'm using a test Splunk Free that will expired on a couple of weeks.
You must be on the Splunk 60-days Enterprise license, and not the Splunk 'free' license as you have mentioned. The 'free' license does not expire until 2038, which is a long time to go from now.
If you are on the 60-days Enterprise license, after the date you would be prompted to convert to the 'free' license if you wish to continue trying out Splunk. Or you may contact Splunk Sales to see if there is a possibility to extend the trial license for your evaluation purposes.