On Cisco IOS you can suspend any actively running process (ping, traceroute, etc. ) using the Ctrl-Shift-6, X (^^X) key sequence. (The X is only needed through a Modem connection). This is the default behavior, we can change this using escape-character command under the line vty x y section.
Now sometimes we initiate telnet connection from a router/switch to another IOS device. In this case using the above method will suspend the telnet connection itself.
So how can we stop a traceroute started on the second device?
We can found the solution in the command reference: “To send an escape sequence over a Telnet connection, press Ctrl-Shift-6 twice.”
So if you are configuring the device through an access server, you can always suspend a process on the second device using the CTRL – SHIFT – 6 – 6 key sequence!