Just checked the Event logs and found following entry-
Login to iSCSI target
iqn.2006-01.com.openfiler:tsn.d5ce1676c1f9 on
vmhba33 @ vmk1 failed. Target returned login
error of: 0203.
error
16/10/2014 11:15:01
esx1.localdomain
Not sure how, IP address is mapped and allowed.