Transferring files from one computer to another is one of the most common tasks expected from a networking or internetworking environment. As a matter of fact, the greatest volume of data exchange in the Internet today is due to file transfer. In this chapter, we discuss two protocols involved in transferring files: File Transfer Protocol (FTP) and Trivial File Transfer Protocol (TFTP). | Chapter 21 Trivial File Transfer Protocol (TFTP) CONTENTS MESSAGES CONNECTION DATA TRANSFER UDP PORTS TFTP EXAMPLE TFTP OPTIONS SECURITY APPLICATIONS TFTP uses the services of UDP on the well-known port 69. MESSAGES Figure 21-1 Message categories Figure 21-2 RRQ Read request Mode: netascii or octet Figure 21-3 WRQ Write request Figure 21-4 DATA format Figure 21-5 ACK format Figure 21-6 ERROR format CONNECTION Figure 21-7 Connection establishment DATA TRANSFER Figure 21-8 Sorcerer’s apprentice bug UDP PORTS Figure 21-9 UDP port numbers used by TFTP TFTP EXAMPLE Figure 21-10 TFTP example TFTP OPTIONS SECURITY Figure 21-11 TELNET with FTP for security APPLICATIONS Figure 21-12 Use of TFTP with BOOTP | Chapter 21 Trivial File Transfer Protocol (TFTP) CONTENTS MESSAGES CONNECTION DATA TRANSFER UDP PORTS TFTP EXAMPLE TFTP OPTIONS SECURITY APPLICATIONS TFTP uses the services of UDP on the well-known port 69. MESSAGES Figure 21-1 Message categories Figure 21-2 RRQ Read request Mode: netascii or octet Figure 21-3 WRQ Write request Figure 21-4 DATA format Figure 21-5 ACK format Figure 21-6 ERROR format CONNECTION Figure 21-7 Connection establishment DATA TRANSFER Figure 21-8 Sorcerer’s apprentice bug UDP PORTS Figure 21-9 UDP port numbers used by TFTP TFTP EXAMPLE Figure 21-10 TFTP example TFTP OPTIONS SECURITY Figure 21-11 TELNET with FTP for security APPLICATIONS Figure 21-12 Use of TFTP with BOOTP | Chapter 21 Trivial File Transfer Protocol (TFTP) CONTENTS MESSAGES CONNECTION DATA TRANSFER UDP PORTS TFTP EXAMPLE TFTP OPTIONS SECURITY APPLICATIONS TFTP uses the services of UDP on the well-known port 69. MESSAGES Figure 21-1 Message categories Figure 21-2 RRQ Read request Mode: netascii or octet Figure 21-3 WRQ Write request Figure 21-4 DATA format Figure 21-5 ACK format Figure 21-6 ERROR format CONNECTION Figure 21-7 Connection establishment DATA TRANSFER Figure 21-8 Sorcerer’s apprentice bug UDP PORTS Figure 21-9 UDP port numbers used by TFTP TFTP EXAMPLE Figure 21-10 TFTP example TFTP OPTIONS SECURITY Figure 21-11 TELNET with FTP for security APPLICATIONS Figure 21-12 Use of TFTP with . | Chapter 21 Trivial File Transfer Protocol (TFTP) CONTENTS MESSAGES CONNECTION DATA TRANSFER UDP PORTS TFTP EXAMPLE TFTP OPTIONS SECURITY APPLICATIONS TFTP uses the services of UDP on the well-known port 69. MESSAGES Figure 21-1 Message categories Figure 21-2 RRQ Read request Mode: netascii or octet Figure 21-3 WRQ Write request Figure 21-4 DATA format Figure 21-5 ACK format Figure 21-6 ERROR format CONNECTION Figure 21-7 Connection establishment DATA TRANSFER Figure 21-8 Sorcerer’s apprentice bug UDP PORTS Figure 21-9 UDP port numbers used by TFTP TFTP EXAMPLE Figure 21-10 TFTP example TFTP OPTIONS SECURITY Figure 21-11 TELNET with FTP for security APPLICATIONS Figure 21-12 Use of TFTP with BOOTP
