CertiGuide to A+ (A+ 4 Real)  9  Chapter 14: Networks       9  The Internet            9  Internet Application Technologies

SMTP 1 DNS

Telnet provides an interactive “character terminal” window on the computer through which you can access remote devices such as routers, for configuration and statistics-gathering purposes. Telnet is also useful when connecting to computers that support a character-based interface such as systems running Linux, other flavors of UNIX or other Operating Systems such as VMS.

While Windows NT has the ability to accept incoming TELNET connections, not all OS features available in the standard GUI are available in the command-line window provided by telnet, so it is of limited usefulness.

A common troubleshooting option is to use TELNET to connect to a system with a port other than the default of port 23 to ascertain communication challenges. For example, using TELNET with port 25 to connect to a SMTP server can yield information about a SMTP connection. On Windows, you can connect via the telnet protocol using the command line TELNET.EXE program. As with FTP, you can generally find more elegant interfaces for the use of TELNET in third party programs, both shareware and commercial.

TELNET uses port 23.

SMTP 1 DNS