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Chapter 19 File Transfer: FTP and TFTP Objectives Upon completion you will be able to: • Understand the connections needed for FTP file transfer • Be familiar with FTP commands and responses • Know the differences between FTP and TFTP • Be familiar with TFTP message types • Understand TFTP flow and error control TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 19.1 FILE TRANSFER PROTOCOL (FTP) File Transfer Protocol (FTP) is the standard mechanism provided by TCP/IP for copying a file from one host to another The topics discussed in this section include: Connections Communication Command Processing File Transfer Anonymous FTP TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt Note: FTP uses the services of TCP It needs two TCP connections The well-known port 21 is used for the control connection and the wellknown port 20 for the data connection TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt Figure 19.1 FTP TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt Figure 19.2 Opening the control connection TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt Figure 19.3 Creating the data connection TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt Figure 19.4 Using the control connection TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt Figure 19.5 Using the data connection TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt Figure 19.6 Command processing TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt Table 19.1 Access commands TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 10 Example bin ftp > close 221 Goodbye ftp > quit TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 34 19.2 TRIVIAL FILE TRANSFER PROTOCOL (TFTP) Trivial File Transfer Protocol (TFTP) is a simple file transfer protocol without the sophisticated features of FTP The topics discussed in this section include: Messages Connection Data Transfer UDP Ports TFTP Example TFTP Options Security Applications TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 35 Note: TFTP uses the services of UDP on the well-known port 69 TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 36 Figure 19.10 Message categories TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 37 Figure 19.11 RRQ format TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 38 Figure 19.12 WRQ format TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 39 Figure 19.13 DATA format TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 40 Figure 19.14 ACK format TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 41 Figure 19.15 ERROR format TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 42 Table 19.8 Error numbers and their meanings TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 43 Figure 19.16 Connection establishment TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 44 Figure 19.17 Sorcerer’s apprentice bug TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 45 Figure 19.18 UDP port numbers used by TFTP TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 46 Figure 19.19 TFTP example TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 47 Figure 19.20 Use of TFTP with BOOTP TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 48 ... https://fb.com/tailieudientucntt 34 19.2 TRIVIAL FILE TRANSFER PROTOCOL (TFTP) Trivial File Transfer Protocol (TFTP) is a simple file transfer protocol without the sophisticated features of FTP The topics discussed...19.1 FILE TRANSFER PROTOCOL (FTP) File Transfer Protocol (FTP) is the standard mechanism provided by TCP/IP for copying a file from one host to another The topics... Messages Connection Data Transfer UDP Ports TFTP Example TFTP Options Security Applications TCP/IP Protocol Suite CuuDuongThanCong.com https://fb.com/tailieudientucntt 35 Note: TFTP uses the services