|  | 8.7 | TCP/IP Suite: Utilities
| 8.7.7 | How and when to use FTP to test, validate, and troubleshoot IP connectivity

File Transfer Protocol, which uses ports 20 and 21, is a protocol designed to transfer data across a network. Variations of the ftp command are shown in the table. Options to Customize FTP for Specific Needs:
Command | Action
ftp -v | Suppresses any display server response.
ftp -n | Prevents automatic login.
ftp -l | Turns off interactive prompting during file transfer
ftp -d | Displays all ftp commands between the client and server for debugging.
ftp -g | Disables the gobbling capacity.
ftp -s: <filename> example: ftp -s:network.doc | Runs the text file containing specific ftp commands.
ftp <hostname> example: ftp www.cisco.com | Connects to the host
In order to use FTP to connect to an address or target machine, like Telnet, FTP must be able to resolve the host name to the IP address of the destination machine in order to communicate. Once the connection and login has been made, users can transfer files and manage directories. Once connected with the remote computer, commands to navigate around the server include:
Commands | Action
CD | Change working directory.
DELETE | To delete files.
LS | To list current directory contents.
BYE | To end connection and log out.
GET | To download a file.
PUT | To upload a file.
VERBOSE | Turns verbose mode on and off.
A common use of troubleshooting with FTP is researching and downloading patches or fixes. For example, Microsoft provides an online FTP server, where patches, upgrades, and the like can be downloaded. Most vendors provide some type of FTP server for users to retrieve these utilities from.