The connection is cut off by system due to no operation for long after the Sun server is telneted.
There are two methods to solve the problem:
1.Modify the configuration file /etc/default/login:
# TIMEOUT sets the number of seconds (between 0 and 900) to wait
# abandoning a login session.
The TIMEOUT option defines the stand-by period caused by user’s unused leave, note TIMEOUT=300 with #, then wq!, Save and exit. It is available after you restart the server.
2.Modify the TIMEOUT value to 100,000,000:
TIMEOUT=100000000, then wq!, Save and exit. It is available after you restart the server. It can avoid being cut off by system due to long stand-by period.