FTP

Introduction

File Transfer Protocol RFC 959 Transfer file to / from remote host Client / Server architecture Separate control, data connection FTP server control connection : port

21

Model for FTP (1/2)

ServerPI

ServerDTP

UserDTP

UserPI

UserInterface

FTP Command

FTP Replies

DataConnection

Server-FTP USER-FTP

FileSystem

FileSystem

User

Model for FTP (2/2)

PI : The protocol interpreter DTP : The data transfer process

establishes and manages the data connection

The Data connection may be used in either direction

The data connection need not exist all of the time

FTP Command (1/3) USER

Syntax : USER username Used to send the user identification to the server Response : 331 (username okay, need password)

PASS Syntax : PASS password Used to send password to the server Response : 230 (user logged in)

PWD Syntax : PWD Used to get the current working directory Response : 257 (current directory)

FTP Command (2/3) PASV

Syntax : PASV Used to request the server to listen on a data port Response : 227 (entering passive mode) The response includes the host and port address this

server is listening on Ex : 163.112.28.104.19.196

IP : 163.112.28.104 Port : 19x256+196 = 5060

LIST Syntax : LIST Used to ask the server to send back a list of all the

files in the current remote directory

FTP Command (3/3) CWD

Syntax : CWD pathname Used to change working directory Response : 250 (Request file action okay)

TYPE Syntax : TYPE type Response : 200

RETR Syntax : RETR filename Used to get a file from the current directory of the re

mote host

NOTE

We must append “\r\n” to the end of FTP command

LoginClientClient

Control Port

ControlPort(21)

ServerServer

TCP connection

220 ready

USER username

331 password require

PASS password

230 user username logged in

Print Working DirectoryClientClient

Control Port

ControlPort(21)

ServerServer

PWD

257 “/” is current direction

List Files in Current DirectoryClientClient

Control Port

ControlPort(21)

ServerServer

PASV

227 Entering Passive Mode(163.112.28.104.19.19619.196)

LIST

DataPort

DataPort

TCP connectionPort:5060150 Data Connection

FTP-DA

Close TCP connection

226 Transfer ok

Change Working DirectoryClientClient

Control Port

ControlPort(21)

ServerServer

CWD pathname

250 CWD command successful

Download File (1/2)ClientClient

Control Port

ControlPort(21)

ServerServer

DataPort

DataPort

Type I

200 Type set to I

PASV

227 Entering Passive Mode

RETR filename

TCP connection

150 Data Connection

FTP-DA ( 傳檔案 )

Download File (2/2)ClientClient

Control Port

ControlPort(21)

ServerServer

DataPort

DataPort

Close TCP connection

226 file send ok

Resource

RFC 959, http://www.ietf.org Ethereal, http://www.ethereal.com

評分標準 基本功能 ( 共 85%)

顯示所有傳送出和接收到的訊息 (5%) 使用帳號和密碼登入 FTP Server (15%) 顯示目前所在工作目錄 (10%) 列出目前工作目錄內容 (15%) 切換工作目錄 (10%) 下載 FTP Server 端的檔案至本機端磁碟中 (25%) 結束與 FTP Server 的連線 (5%)

書面報告 ( 共 10%) 程式架構與寫法介紹 (5%) 程式功能與操作方法 (5%)

程式註解 (5%) 其他功能 (Bonus)

上傳檔案至 FTP Server (10%) 可同時下載多個檔案 (10%)

繳交日期 94 年 5 月 9 日 24:00 前 於截止時間前將 Source Code 寄至

network2006@csie.ntu.edu.tw Demo 地點 : R219 Demo 時段

5/10 ( 三 ) 5/11 ( 四 )

請於 Demo 前一週至 R442 門口填表預約時段

注意事項 可以使用任何程式語言 不可使用和 FTP 相關的 API Demo 時當場以截止繳交日期前寄出的 source code 編譯執行

檔 執行環境以 R219 電腦中可提供的為主 , 如使用特殊的 Compil

er, 請自行準備執行環境 作業驗收標準以可在 R219 之電腦執行為準 , 若 Demo 時程式

無法於 R219 之電腦執行 , 則視同作業未完成 ( 可自備執行環境 , 工作站上亦可 )

作業驗收時 , 只要能通過指定的 FTP Server 之測試即可 作業請勿抄襲 Demo 時請攜帶書面報告紙本 , 並於封面註明姓名與學號