Telnet

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…or tools such as Gopher that 'save' end users from having to deal with the command line prompt and the peculiar details of commands like Telnet. While that may be the case, the tendency remains in place for programmers to develop new software by building on the old. Therefore, knowing the underlying command structure of older protocols like telnet and rlogin are likely to remain essential skills for the networking professional in the forseeable future.