SSH

commands:

sudo killall ssh

http://askubuntu.com/questions/218797/cant-connect-to-my-ssh-remotely

netstat -nr
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         192.168.1.1     0.0.0.0         UG        0 0          0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U         0 0          0 eth0

Find the gateway, for me it is 192.168.1.1. Next, try connecting to it through ssh:

ssh 192.168.1.1

try ssh -v to see at which point it stops. –

上班族ssh tunnel求生手冊

http://www.ubuntu-tw.org/modules/newbb/viewtopic.php?viewmode=compact&topic_id=17538&forum=7

(利用SSH Tunnel 逃離 MIS 掌控魔爪) 

使用ping掃瞄子網路內的所有IP，並列出有回應的IP，不作進一步測試。

Install telnetd server

$ sudo apt-get install telnetd
Restart inetd service:

$ sudo /etc/init.d/openbsd-inetd restart
You should now be able to telnet to the server from Windows or Linux desktop system to Ubentu Linux telnet server. Type the following command to connect to Telnet server:
$ telnet ubentu-linux-server-ip
$ telnet 192.168.1.200
$ telnet ubentu.mydomain.com

http://superuser.com/questions/353935/ping-works-while-telnet-fails

http://stackoverflow.com/questions/9447226/how-to-close-this-ssh-tunnel