When I tried pulling jenkins images(docker pull jenkins) from docker hub,at the time of download it reports the authentication required error.
Please suggest.

When I tried pulling jenkins images(docker pull jenkins) from docker hub,at the time of download it reports the authentication required error.
Please suggest.

Try executing a
docker logoutbefore pulling the image. Similar issue here.It also can be related to server/client time syncrony, so if
docker logoutdoes not work check if the time of your system is correct (can be in a different timezone). And set it withsudo date -s "28 NOV 2013 hh:mm:ss", you can check the current exact hour here.