set a limit on concurrent SSH/SFTP connections to 2 per user

I made the changes in /etc/security/limits.conf test hard maxlogins 2 sftptest hard maxlogins 2 - After above entries I have tested below scenarios 1. Open 2 putty sessions when I tried to open 3rd sessions it disconnect automatically (Working fine with ssh user not for sftp user ) 2. Open 2 putty sessions when I am trying to open 3rd session from the filezilla / winscp connection disconnected automatically (Working fine with ssh user ) 3.When I am trying to open 3 sessions in filezilla/winscp I am able to open 3 sessions ( Not working) 4. when I am trying to open 3 sessions in filezilla/winscp with sftp users I am able to open all three sessions -Is there any difference in putty client and winscp/filezilla ? -SSH users having shell login but sftp users don't have shell login - Is there any chance to limit the connections 2 for sftp users? I am pretty new to Linux.