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in.ftpd(1m) [redhat man page]

in.ftpd(1M)						  System Administration Commands					       in.ftpd(1M)

in.ftpd, ftpd - File Transfer Protocol Server SYNOPSIS
in.ftpd [-4] [-A] [-a] [-C] [-d] [-I] [-i] [-K] [-L] [-l] [-o] [-P dataport] [-p ctrlport] [-Q] [-q] [-r rootdir] [-S] [-s] [-T maxtimeout] [-t timeout] [-u umask] [-V] [-v] [-W] [-w] [-X] DESCRIPTION
in.ftpd is the Internet File Transfer Protocol (FTP) server process. The server may be invoked by the Internet daemon inetd(1M) each time a connection to the FTP service is made or run as a standalone server. See services(4). OPTIONS
in.ftpd supports the following options: -4 When running in standalone mode, listen for connections on an AF_INET type socket. The default is to listen on an AF_INET6 type socket. -a Enables use of the ftpaccess(4) file. -A Disables use of the ftpaccess(4) file. Use of ftpaccess is disabled by default. -C Non-anonymous users need local credentials (for example, to authenticate to remote fileservers). So they should be prompted for a password unless they forwarded credentials as part of authentication. -d Writes debugging information to syslogd(1M). -i Logs the names of all files received by the FTP Server to xferlog(4). You can override the -i option through use of the ftpaccess(4) file. -I Disables the use of AUTH and ident to determine the username on the client. See RFC 931. The FTP Server is built not to use AUTH and ident. -K Connections are only allowed for users who can authenticate through the ftp AUTH mechanism. (Anonymous ftp may also be allowed if it is configured.) ftpd will ask the user for a password if one is required. -l Logs each FTP session to syslogd(1M). -L Logs all commands sent to in.ftpd to syslogd(1M). When the -L option is used, command logging will be on by default, once the FTP Server is invoked. Because the FTP Server includes USER commands in those logged, if a user accidentally enters a password instead of the username, the password will be logged. You can override the -L option through use of the ftpac- cess(4) file. -o Logs the names of all files transmitted by the FTP Server to xferlog(4). You can override the -o option through use of the ftpaccess(4) file. -P dataport The FTP Server determines the port number by looking in the services(4) file for an entry for the ftp-data service. If there is no entry, the daemon uses the port just prior to the control connection port. Use the -P option to specify the data port number. -p ctrlport When run in standalone mode, the FTP Server determines the control port number by looking in the services(4) file for an entry for the ftp service. Use the -p option to specify the control port number. -Q Disables PID files. This disables user limits. Large, busy sites that do not want to impose limits on the number of concur- rent users can use this option to disable PID files. -q Uses PID files. The limit directive uses PID files to determine the number of current users in each access class. By default, PID files are used. -r rootdir chroot(2) to rootdir upon loading. Use this option to improve system security. It limits the files that can be damaged should a break in occur through the daemon. This option is similar to anonymous FTP. Additional files are needed, which vary from system to system. -S Places the daemon in standalone operation mode. The daemon runs in the background. This is useful for startup scripts that run during system initialization. See init.d(4). -s Places the daemon in standalone operation mode. The daemon runs in the foreground. This is useful when run from /etc/init- tab by init(1M). -T maxtimeout Sets the maximum allowable timeout period to maxtimeout seconds. The default maximum timeout limit is 7200 second (two hours). You can override the -T option through use of the ftpaccess(4) file. -t timeout Sets the inactivity timeout period to timeout seconds. The default timeout period is 900 seconds (15 minutes). You can override the -t option through use of the ftpaccess(4) file. -u umask Sets the default umask to umask. -V Displays copyright and version information, then terminate. -v Writes debugging information to syslogd(1M). -W Does not record user login and logout in the wtmpx(4) file. -w Records each user login and logout in the wtmpx(4) file. By default, logins and logouts are recorded. -X Writes the output from the -i and -o options to the syslogd(1M) file instead of xferlog(4). This allows the collection of output from several hosts on one central loghost. You can override the -X option through use of the ftpaccess(4) file. Requests The FTP Server currently supports the following FTP requests. Case is not distinguished. ABOR Abort previous command. ADAT Send an authentication protocol message. ALLO Allocate storage (vacuously). AUTH Specify an authentication protocol to be performed. Currently only "GSSAPI" is supported. APPE Append to a file. CCC Set the command channel protection mode to "Clear" (no protection). Not allowed if data channel is protected. CDUP Change to parent of current working directory. CWD Change working directory. DELE Delete a file. ENC Send a privacy and integrity protected command (given in argument). EPRT Specify extended address for the transport connection. EPSV Extended passive command request. HELP Give help information. LIST Give list files in a directory (ls -lA). LPRT Specify long address for the transport connection. LPSV Long passive command request. MIC Send an integrity protected command (given in argument). MKD Make a directory. MDTM Show last time file modified. 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. PBSZ Specify a protection buffer size. PROT Specify a protection level under which to protect data transfers. Allowed arguments: clear No protection. safe Integrity protection private Integrity and encryption protection PORT Specify data connection port. PWD Print the current working directory. QUIT Terminate session. REST Restart incomplete transfer. RETR Retrieve a file. RMD Remove a directory. RNFR Specify rename-from file name. RNTO Specify rename-to file name. SITE Use nonstandard commands. SIZE Return size of file. STAT Return status of server. STOR Store a file. STOU Store a file with a unique name. STRU Specify data transfer structure. SYST Show operating system type of server system. TYPE Specify data transfer type. USER Specify user name. XCUP Change to parent of current working directory. This request is deprecated. XCWD Change working directory. This request is deprecated. XMKD Make a directory. This request is deprecated. XPWD Print the current working directory. This request is deprecated. XRMD Remove a directory. This request is deprecated. The following nonstandard or UNIX specific commands are supported by the SITE request: ALIAS List aliases. CDPATH List the search path used when changing directories. CHECKMETHOD List or set the checksum method. CHECKSUM Give the checksum of a file. CHMOD Change mode of a file. For example, SITE CHMOD 755 filename. EXEC Execute a program. For example, SITE EXEC program params GPASS Give special group access password. For example, SITE GPASS bar. GROUP Request special group access. For example, SITE GROUP foo. GROUPS List supplementary group membership. HELP Give help information. For example, SITE HELP. IDLE Set idle-timer. For example, SITE IDLE 60. UMASK Change umask. For example, SITE UMASK 002. The remaining FTP requests specified in RFC 959 are recognized, but not implemented. The FTP server will abort 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 RFC 959. If a STAT command is received during a data transfer that has been preceded by a Telnet IP and Synch, transfer status will be returned. in.ftpd interprets file names according to the "globbing" conventions used by csh(1). This allows users to utilize the metacharacters: * ? [ ] { } ~ in.ftpd authenticates users according to the following rules: First, the user name must be in the password data base, the location of which is specified in nsswitch.conf(4). An encrypted password (an authentication token in PAM) must be present. A password must always be provided by the client before any file operations can be performed. For non-anonymous users, the PAM framework is used to verify that the correct password was entered. See SECURITY below. Second, the user name must not appear in either the /etc/ftpusers or the /etc/ftpd/ftpusers file. Use of the /etc/ftpusers files is depre- cated, although it is still supported. Third, the users must have a standard shell returned by getusershell(3C). Fourth, if the user name is anonymous or ftp, an anonymous ftp account must be present in the password file for user ftp. Use ftpconfig(1M) to create the anonymous ftp account and home directory tree. Fifth, if the GSS-API is used to authenticate the user, then gss_auth_rules(5) determines user access without a password needed. The FTP Server supports virtual hosting, which can be configured by using ftpaddhost(1M). The FTP Server does not support sublogins. General FTP Extensions The FTP Server has certain extensions. If the user specifies a filename that does not exist with a RETR (retrieve) command, the FTP Server looks for a conversion to change a file or directory that does into the one requested. See ftpconversions(4). By convention, anonymous users supply their email address when prompted for a password. The FTP Server attempts to validate these email addresses. A user whose FTP client hangs on a long reply, for example, a multiline response, should use a dash (-) as the first character of the user's password, as this disables the Server's lreply() function. The FTP Server can also log all file transmission and reception. See xferlog(4) for details of the log file format. The SITE EXEC command may be used to execute commands in the /bin/ftp-exec directory. Take care that you understand the security implica- tions before copying any command into the /bin/ftp-exec directory. For example, do not copy in /bin/sh. This would enable the user to exe- cute other commands through the use of sh -c. If you have doubts about this feature, do not create the /bin/ftp-exec directory. SECURITY
For non-anonymous users, in.ftpd uses pam(3PAM) for authentication, account management, and session management. The PAM configuration pol- icy, listed through /etc/pam.conf, specifies the module to be used for in.ftpd. Here is a partial pam.conf file with entries for the in.ftpd command using the UNIX authentication, account management, and session management module. ftp auth requisite ftp auth required ftp auth required ftp account required ftp account required ftp account required ftp session required If there are no entries for the ftp service, then the entries for the "other" service will be used. Unlike login, passwd, and other com- mands, the ftp protocol will only support a single password. Using multiple modules will prevent in.ftpd from working properly. For anonymous users, who by convention supply their email address as a password, in.ftpd validates passwords according to the passwd-check capability in the ftpaccess file. USAGE
The in.ftpd command is IPv6-enabled. See ip6(7P). FILES
/etc/ftpd/ftpaccess FTP Server configuration file /etc/ftpd/ftpconversions FTP Server conversions database /etc/ftpd/ftpgroups FTP Server enhanced group access file /etc/ftpd/ftphosts FTP Server individual user host access file /etc/ftpd/ftpservers FTP Server virtual hosting configuration file. /etc/ftpd/ftpusers File listing users for whom FTP login privileges are disallowed. /etc/ftpusers File listing users for whom FTP login privileges are disallowed. This use of this file is deprecated. /var/log/xferlog FTP Server transfer log file /var/run/ftp.pids-classname /var/adm/wtmpx Extended database files that contain the history of user access and accounting information for the wtmpx database. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWftpu | +-----------------------------+-----------------------------+ |Interface Stability |External | +-----------------------------+-----------------------------+ SEE ALSO
csh(1), ftp(1), ftpcount(1), ftpwho(1), ls(1), svcs(1), ftpaddhost(1M), ftpconfig(1M), ftprestart(1M), ftpshut(1M), inetadm(1M), inetd(1M), svcadm(1M), syslogd(1M), chroot(2), umask(2), getpwent(3C), getusershell(3C), syslog(3C), ftpaccess(4), ftpconversions(4), ftpgroups(4), ftphosts(4), ftpservers(4), ftpusers(4), group(4), passwd(4), services(4), xferlog(4), wtmpx(4), attributes(5), gss_auth_rules(5), pam_authtok_check(5), pam_authtok_get(5), pam_authtok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix_account(5), pam_unix_auth(5), pam_unix_session(5), smf(5), ip6(7P) Allman, M., Ostermann, S., and Metz, C. RFC 2428, FTP Extensions for IPv6 and NATs. The Internet Society. September 1998. Piscitello, D. RFC 1639, FTP Operation Over Big Address Records (FOOBAR). Network Working Group. June 1994. Postel, Jon, and Joyce Reynolds. RFC 959, File Transfer Protocol (FTP ). Network Information Center. October 1985. St. Johns, Mike. RFC 931, Authentication Server. Network Working Group. January 1985. Linn, J., Generic Security Service Application Program Interface Version 2, Update 1, RFC 2743. The Internet Society, January 2000. Horowitz, M., Lunt, S., FTP Security Extensions, RFC 2228. The Internet Society, October 1997. DIAGNOSTICS
in.ftpd logs various errors to syslogd(1M), with a facility code of daemon. NOTES
The anonymous FTP account is inherently dangerous and should be avoided when possible. The FTP Server must perform certain tasks as the superuser, for example, the creation of sockets with privileged port numbers. It maintains an effective user ID of the logged in user, reverting to the superuser only when necessary. The FTP Server no longer supports the /etc/default/ftpd file. Instead of using UMASK=nnn to set the umask, use the defumask capability in the ftpaccess file. The banner greeting text capability is also now set through the ftpaccess file by using the greeting text capability instead of by using BANNER="...". However, unlike the BANNER string, the greeting text string is not passed to the shell for evaluation. See ftpaccess(4). The pam_unix(5) module is no longer supported. Similar functionality is provided by pam_authtok_check(5), pam_authtok_get(5), pam_auth- tok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix_account(5), pam_unix_auth(5), and pam_unix_session(5). The in.ftpd service is managed by the service management facility, smf(5), under the service identifier: svc:/network/ftp Administrative actions on this service, such as enabling, disabling, or requesting restart, can be performed using svcadm(1M). Responsibil- ity for initiating and restarting this service is delegated to inetd(1M). Use inetadm(1M) to make configuration changes and to view config- uration information for this service. The service's status can be queried using the svcs(1) command. SunOS 5.10 4 Aug 2004 in.ftpd(1M)

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