FTPD(8c,C) AIX TCP/IP User's Guide FTPD(8c,C) ------------------------------------------------------------------------------- ftpd PURPOSE Provides the server function for the FTP protocol. SYNTAX +----------------+ /etc/ftpd ---| +------------+ |---| +-| -d |-+ ^| -l || || -ttimeout || || -v || |+------------+| +--------------+ DESCRIPTION The ftpd command is the DARPA Internet File Transfer Protocol server process. The server uses the TCP protocol and listens at the port specified in the FTP service specification (see "services"). The ftpd command is usually started by inetd, a daemon, which listens on the ftp port for requests. FLAGS The ftpd command options are: -d Writes debugging information to the syslog. -l Logs each FTP session in the syslog. -t Sets the inactivity timeout period to timeout, which is given in seconds. There must be no whitespace between -t and timeout. -v Equivalent to -d. The FTP server timeouts an inactive session after 15 minutes. If the -t option is specified, the inactivity timeout period is set to timeout. The FTP server currently supports the following FTP requests. Case is not distinguished. Request Description ABOR Abort previous command ACCT Specify account (ignored) ALLO Allocate storage (vacuously) Processed October 29, 1990 FTPD(8c,C) 1 FTPD(8c,C) AIX TCP/IP User's Guide FTPD(8c,C) APPE Append to a file CDUP Change to parent of current working directory CWD Change working directory DELE Delete a file HELP Give help information LIST Give list files in a directory (ls -lg) MKD Make a directory MODE Specify data transfer mode NLST Give name list of files in directory (ls) NOOP Do nothing PASS Specify password PASV Prepare for server-to-server transfer PORT Specify data connection port PWD Print the current working directory QUIT Terminate session RETR Retrieve a file RMD Remove a directory RNFR Specify rename-from file name RNTO Specify rename-to file name STOR Store a file STOU Store a file with a unique name STRU Specify data transfer structure TYPE Specify data transfer type USER Specify user name XCUP Change to parent of current working directory XCWD Change working directory XMKD Make a directory XPWD Print the current working directory XRMD Remove a directory The FTP server stops an active file transfer only when the abor command is preceded by a TELNET Interrupt Process (IP) signal and a TELNET SYNCH signal in the command TELNET stream, as described in J. Postel and J. Reynolds etal File Transfer Protocol. This command interprets file names according to the globbing conventions used by the C shell. This allows users to utilize the metacharacters * ? [ { } ]. The ftpd command verification users according to the following rules: 1. The user name must be in the password data base, /etc/passwd, and not have a null password. In this case, a password must be provided by the client before any file operations may be performed. 2. The user name must not appear in the file /etc/ftpusers. Note: This file must be created by the system administrator. 3. The user must have a standard shell. 4. If the user name is anonymous or FTP, an anonymous FTP account must be present in the password file (user FTP). In this case, the user is allowed Processed October 29, 1990 FTPD(8c,C) 2 FTPD(8c,C) AIX TCP/IP User's Guide FTPD(8c,C) to log in by specifying any password (by convention this is given as the client host's name). In the last case, ftpd takes special measures to restrict the client's access privileges. The server performs a chroot system call, see AIX Operating System Technical Reference for additional information, to the home directory of the FTP user. In order that system security is not breached, it is recommended that the FTP subtree be constructed with care. The following rules are recommended. ftp Make the home directory owned by FTP and unwritable by anyone. ftp/bin Make this directory owned by the superuser and unwritable by anyone. The program ls, refer to AIX Operating System Command Reference, must be present to support the list commands. This program should have mode 111. Processed October 29, 1990 FTPD(8c,C) 3 FTPD(8c,C) AIX TCP/IP User's Guide FTPD(8c,C) ftp/etc Make this directory owned by the superuser and unwritable by anyone. The files passwd and group (see AIX Operating System Technical Reference) must be present for the ls command to work properly. These files should be mode 444. ftp/pub Make this directory mode 777 and owned by FTP. Users should then place files, which are to be accessible via the anonymous account, in this directory. RELATED INFORMATION In this book: "ftp" Processed October 29, 1990 FTPD(8c,C) 4