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diff --git a/usr/src/man/man4/hosts_options.4 b/usr/src/man/man4/hosts_options.4 new file mode 100644 index 0000000000..3126505b8b --- /dev/null +++ b/usr/src/man/man4/hosts_options.4 @@ -0,0 +1,192 @@ +'\" t +.\" +.\" Modified for Solaris to to add the Solaris stability classification, +.\" and to add a note about source availability. +.\" +.TH HOSTS_OPTIONS 4 +.SH NAME +hosts_options \- host access control language extensions +.SH DESCRIPTION +This document describes optional extensions to the language described +in the hosts_access(4) document. The extensions are enabled at program +build time. For example, by editing the Makefile and turning on the +PROCESS_OPTIONS compile-time option. +.PP +The extensible language uses the following format: +.sp +.ti +3 +daemon_list : client_list : option : option ... +.PP +The first two fields are described in the hosts_access(4) manual page. +The remainder of the rules is a list of zero or more options. Any ":" +characters within options should be protected with a backslash. +.PP +An option is of the form "keyword" or "keyword value". Options are +processed in the specified order. Some options are subjected to +%<letter> substitutions. For the sake of backwards compatibility with +earlier versions, an "=" is permitted between keyword and value. +.SH LOGGING +.IP "severity mail.info" +.IP "severity notice" +Change the severity level at which the event will be logged. Facility +names (such as mail) are optional, and are not supported on systems +with older syslog implementations. The severity option can be used +to emphasize or to ignore specific events. +.SH ACCESS CONTROL +.IP "allow" +.IP "deny" +Grant (deny) service. These options must appear at the end of a rule. +.PP +The \fIallow\fR and \fIdeny\fR keywords make it possible to keep all +access control rules within a single file, for example in the +\fIhosts.allow\fR file. +.sp +To permit access from specific hosts only: +.sp +.ne 2 +.ti +3 +ALL: .friendly.domain: ALLOW +.ti +3 +ALL: ALL: DENY +.sp +To permit access from all hosts except a few trouble makers: +.sp +.ne 2 +.ti +3 +ALL: .bad.domain: DENY +.ti +3 +ALL: ALL: ALLOW +.sp +Notice the leading dot on the domain name patterns. +.SH RUNNING OTHER COMMANDS +.IP "spawn shell_command" +Execute, in a child process, the specified shell command, after +performing the %<letter> expansions described in the hosts_access(4) +manual page. The command is executed with stdin, stdout and stderr +connected to the null device, so that it won\'t mess up the +conversation with the client host. Example: +.sp +.nf +.ti +3 +spawn (/some/where/safe_finger -l @%h | /usr/ucb/mail root) & +.fi +.sp +executes, in a background child process, the shell command "safe_finger +-l @%h | mail root" after replacing %h by the name or address of the +remote host. +.sp +The example uses the "safe_finger" command instead of the regular +"finger" command, to limit possible damage from data sent by the finger +server. The "safe_finger" command is part of the daemon wrapper +package; it is a wrapper around the regular finger command that filters +the data sent by the remote host. +.IP "twist shell_command" +Replace the current process by an instance of the specified shell +command, after performing the %<letter> expansions described in the +hosts_access(4) manual page. Stdin, stdout and stderr are connected to +the client process. This option must appear at the end of a rule. +.sp +To send a customized bounce message to the client instead of +running the real ftp daemon: +.sp +.nf +.ti +3 +in.ftpd : ... : twist /bin/echo 421 Some bounce message +.fi +.sp +For an alternative way to talk to client processes, see the +\fIbanners\fR option below. +.sp +To run /some/other/in.telnetd without polluting its command-line +array or its process environment: +.sp +.nf +.ti +3 +in.telnetd : ... : twist PATH=/some/other; exec in.telnetd +.fi +.sp +Warning: in case of UDP services, do not twist to commands that use +the standard I/O or the read(2)/write(2) routines to communicate with +the client process; UDP requires other I/O primitives. +.SH NETWORK OPTIONS +.IP "keepalive" +Causes the server to periodically send a message to the client. The +connection is considered broken when the client does not respond. The +keepalive option can be useful when users turn off their machine while +it is still connected to a server. The keepalive option is not useful +for datagram (UDP) services. +.IP "linger number_of_seconds" +Specifies how long the kernel will try to deliver not-yet delivered +data after the server process closes a connection. +.SH USERNAME LOOKUP +.IP "rfc931 [ timeout_in_seconds ]" +Look up the client user name with the RFC 931 (TAP, IDENT, RFC 1413) +protocol. This option is silently ignored in case of services based on +transports other than TCP. It requires that the client system runs an +RFC 931 (IDENT, etc.) -compliant daemon, and may cause noticeable +delays with connections from non-UNIX clients. The timeout period is +optional. If no timeout is specified a compile-time defined default +value is taken. +.SH MISCELLANEOUS +.IP "banners /some/directory" +Look for a file in `/some/directory' with the same name as the daemon +process (for example in.telnetd for the telnet service), and copy its +contents to the client. Newline characters are replaced by +carriage-return newline, and %<letter> sequences are expanded (see +the hosts_access(4) manual page). +.sp +The tcp wrappers source code distribution provides a sample makefile +(Banners.Makefile) for convenient banner maintenance. +.sp +Warning: banners are supported for connection-oriented (TCP) network +services only. +.IP "nice [ number ]" +Change the nice value of the process (default 10). Specify a positive +value to spend more CPU resources on other processes. +.IP "setenv name value" +Place a (name, value) pair into the process environment. The value is +subjected to %<letter> expansions and may contain whitespace (but +leading and trailing blanks are stripped off). +.sp +Warning: many network daemons reset their environment before spawning a +login or shell process. +.IP "umask 022" +Like the umask command that is built into the shell. An umask of 022 +prevents the creation of files with group and world write permission. +The umask argument should be an octal number. +.IP "user nobody" +.IP "user nobody.kmem" +Assume the privileges of the "nobody" userid (or user "nobody", group +"kmem"). The first form is useful with inetd implementations that run +all services with root privilege. The second form is useful for +services that need special group privileges only. +.SH DIAGNOSTICS +When a syntax error is found in an access control rule, the error +is reported to the syslog daemon; further options will be ignored, +and service is denied. +.SH SEE ALSO +hosts_access(4), the default access control language +.SH AUTHOR +.na +.nf +Wietse Venema (wietse@wzv.win.tue.nl) +Department of Mathematics and Computing Science +Eindhoven University of Technology +Den Dolech 2, P.O. Box 513, +5600 MB Eindhoven, The Netherlands +\" @(#) hosts_options.5 1.10 94/12/28 17:42:28 +.\" Begin Sun update +.SH ATTRIBUTES +See +.BR attributes (5) +for descriptions of the following attributes: +.sp +.TS +box; +cbp-1 | cbp-1 +l | l . +ATTRIBUTE TYPE ATTRIBUTE VALUE += +Interface Stability Committed +.TE +.\" End Sun update |