Unable to connect to Oracle from SQL Developer below is the error  


  Status : Failure -Io exception: The Network Adapter could not
  establish the connection


It's connecting from my system but unable to connect from other systems on the network.
ping command is working fine and tnsping is also working. any suggestion and help is very helpful.

problem resolved thanks for the support..It wasn't the database fault...It was an network issue....
This seems to be a hostname resolution problem. Please try to connect to the IP address instead of the hostname.

If this is not the solution could you please post the output of the following command:

lsnrctl status


EDIT 1:

LISTENER = 
(DESCRIPTION_LIST = 
  (DESCRIPTION = 
    (ADDRESS = 
      (PROTOCOL = IPC)(KEY = EXTPROC1521)
    )
    (ADDRESS = 
      (PROTOCOL = TCP)(HOST = 192.168.2.64)(PORT = 1521)
    )
  )
)


EDIT 2:

It turned out to be an firewall problem. See comments below.