强制终止远程登陆用户的TCP链接

Some of my cisco devices I am not able to clear idle vty lines. if I give clear line it is asking for confirmation but those lines are not getting cleared.TCP keepalive services are aliready enabled

2611# show tcp brief

TCB Local Address Foreign Address (state)

81FC42B0 10.0.0.15.23 161.108.216.38.1660 ESTAB

2611#clear tcp tcb 81FC42B0