現在假設 joe 想要使用 ftp 來從 denver.acme.com 機器中的 ~joe/MAIL 目錄中獲取他的郵件,他就必須加密作業階段。其交換動作如下﹕
% ftp -f denver.acme.com Connected to denver.acme.com 220 denver.acme.org FTP server (Version 6.0) ready. 334 Using authentication type GSSAPI; ADAT must follow GSSAPI accepted as authentication type GSSAPI authentication succeeded Name (daffodil.acme.org:joe) 232 GSSAPI user joe@MELPOMENE.ACME.COM is authorized as joe 230 User joe logged in. Remote system type is UNIX. Using BINARY mode to transfer files. ftp> protect private 200 Protection level set to Private ftp> cd ~joe/MAIL 250 CWD command successful. ftp> get RMAIL 227 Entering Passive Mode (128,0,0,5,16,49) 150 Opening BINARY mode data connection for RMAIL (158336 bytes). 226 Transfer complete. 158336 bytes received in 1.9 seconds (1.4e+02 Kbytes/s) ftp> quit % |
要加密作業階段,joe 將保護等級設定為 private。