Telnet Time Trick
When you type in the telnet command we usually stop after the host identifier. When no port is specified telnet defaults to the telnet port #23. We can redirect however; port 13 is the daytime port (RFC 867). So to find out the system time of a remote system:
$ telnet 192.168.1.102 13
Connected to sparc5-110.
Escape character is ‘^]’.
Mon Sep 26 14:16:29 2005
Connection closed by foreign host.
The screen may blank, the date/time stamp from the end host will be echoed, and a “Connection to host lost” message will be printed.