2. ● It uses two TCP Ports
● -one for control
● -one for data transfers It’s a command-response protocol
● It’s control port uses telnet protocol to negotiate session
● -US-ASCII
● -<crlf> is end-of-line character
FTP ● INTRODUCTION
3.
4. Transferring Files in a Heterogeneous Host
Environment
Due to multiple hardware types and operating systems file are converted to
four environmentally neutral data type for transport and the converted to
local types at the destination
-ASCII
-EBCDIC
-IMAGE
-LOCAL
A NVT-ASCII
E EBCDIC Text
I Raw binary, series of octets
L Raw binary using a variable byte
size
Client responsibility to tell server data type to use Default data type, unless
otherwise specified is ASCII
5. FTP Commands – Some of the FTP commands are :
USER – This command sends the user identification to the server.
PASS – This command sends the user password to the server.
CWD – This command allows the user to work with a different directory or dataset for file storage or retrieval without altering his login
or accounting information.
RMD – This command causes the directory specified in the path-name to be removed as a directory.
MKD – This command causes the directory specified in the path name to be created as a directory.
PWD – This command causes the name of the current working directory to be returned in the reply.
RETR – This command causes the remote host to initiate a data connection and to send the requested file over the data connection.
STOR – This command causes to store a file into the current directory of the remote host.
LIST – Sends a request to display the list of all the files present in the directory.
ABOR – This command tells the server to abort the previous FTP service command and any associated transfer of data.
QUIT – This command terminates a USER and if file transfer is not in progress, the server closes the control connection.
FTP Replies – Some of the FTP replies are :
200 Command okay.
530 Not logged in.
331 User name okay, need password.
225 Data connection open; no transfer in progress.
221 Service closing control connection.
551 Requested action aborted: page type unknown.
502 Command not implemented.
503 Bad sequence of commands.
504 Command not implemented for that parameter.
7. LITERATURE
REVIEW
CONCLUSION
BIBLIOGRAPHY
• The original specification for the File Transfer Protocol
was written by Abhay Bhushan and published
as RFC 114 on 16 April 1971. Until 1980, FTP ran
on NCP, the predecessor of TCP/IP. The protocol was
later replaced by a TCP/IP version, RFC 765 (June
1980) and RFC 959 (October 1985), the current
specification. Several proposed standards
amend RFC 959, for example RFC 1579 (February
1994) enables Firewall-Friendly FTP (passive
mode), RFC 2228 (June 1997) proposes security
extensions, RFC 2428 (September 1998) adds support
for IPv6 and defines a new type of passive mode.
• FTP does not encrypt its traffic; all transmissions are in
clear text, and usernames, passwords, commands and
data can be read by anyone able to perform packet capture
(sniffing) on the network.[2][16] This problem is common to
many of the Internet Protocol specifications (such
as SMTP, Telnet, POP and IMAP) that were designed
prior to the creation of encryption mechanisms such
as TLS or SSL.[4]
• Common solutions to this problem include:
• Using the secure versions of the insecure protocols,
e.g., FTPS instead of FTP and TelnetS instead of Telnet.
• Using a different, more secure protocol that can handle the
job, e.g. SSH File Transfer Protocol or Secure Copy
Protocol.
• Using a secure tunnel such as Secure Shell (SSH)
or virtual private network (VPN).
• https://bit.ly/2QWDQ0R
• https://bit.ly/2OUvg0X
