.\" manual page [] for pppd 2.3
-.\" $Id: pppd.8,v 1.32 1999/03/02 05:32:30 paulus Exp $
+.\" $Id: pppd.8,v 1.34 1999/03/12 06:07:19 paulus Exp $
.\" SH section heading
.\" SS subsection heading
.\" LP paragraph
.I <tty_name>
Communicate over the named device. The string "/dev/" is prepended if
necessary. If no device name is given, or if the name of the terminal
-connected to the standard input is given, pppd
-will use that terminal, and will not fork to put itself in the
-background. This option is privileged.
+connected to the standard input is given, pppd will use that terminal,
+and will not fork to put itself in the background. A value for this
+option from a privileged source cannot be overridden by a
+non-privileged user.
.TP
.I <speed>
Set the baud rate to <speed> (a decimal number). On systems such as
4.4BSD and NetBSD, any speed can be specified. Other systems
(e.g. SunOS) allow only a limited set of speeds.
.TP
-.B active-filter \fIfilter-expression
-Specifies a packet filter to be applied to data packets to determine
-which packets are to be regarded as link activity, and therefore reset
-the idle timer, or cause the link to be brought up in demand-dialling
-mode. This option is useful in conjunction with the
-\fBidle\fR option if there are packets being sent or received
-regularly over the link (for example, routing information packets)
-which would otherwise prevent the link from ever appearing to be idle.
-The \fIfilter-expression\fR syntax is as described for tcpdump(1),
-except that qualifiers which are inappropriate for a PPP link, such as
-\fBether\fR and \fBarp\fR, are not permitted. Generally the filter
-expression should be enclosed in single-quotes to prevent whitespace
-in the expression from being interpreted by the shell. This option
-is currently only available under NetBSD, and then only
-if both the kernel and pppd were compiled with PPP_FILTER defined.
-.TP
.B asyncmap \fI<map>
Set the async character map to <map>. This map describes which
control characters cannot be successfully received over the serial
.B connect \fIscript
Use the executable or shell command specified by \fIscript\fR to set
up the serial line. This script would typically use the chat(8)
-program to dial the modem and start the remote ppp session. This
-option is privileged if the \fInoauth\fR option is used.
+program to dial the modem and start the remote ppp session. A value
+for this option from a privileged source cannot be overridden by a
+non-privileged user.
.TP
.B crtscts
Use hardware flow control (i.e. RTS/CTS) to control the flow of
pppd has terminated the link. This script could, for example, issue
commands to the modem to cause it to hang up if hardware modem control
signals were not available. The disconnect script is not run if the
-modem has already hung up. This option is privileged if the
-\fInoauth\fR option is used.
+modem has already hung up. A value for this option from a privileged
+source cannot be overridden by a non-privileged user.
.TP
.B escape \fIxx,yy,...
Specifies that certain characters should be escaped on transmission
negotiation, unless the \fIipcp-accept-local\fR and/or
\fIipcp-accept-remote\fR options are given, respectively.
.TP
+.B active-filter \fIfilter-expression
+Specifies a packet filter to be applied to data packets to determine
+which packets are to be regarded as link activity, and therefore reset
+the idle timer, or cause the link to be brought up in demand-dialling
+mode. This option is useful in conjunction with the
+\fBidle\fR option if there are packets being sent or received
+regularly over the link (for example, routing information packets)
+which would otherwise prevent the link from ever appearing to be idle.
+The \fIfilter-expression\fR syntax is as described for tcpdump(1),
+except that qualifiers which are inappropriate for a PPP link, such as
+\fBether\fR and \fBarp\fR, are not permitted. Generally the filter
+expression should be enclosed in single-quotes to prevent whitespace
+in the expression from being interpreted by the shell. This option
+is currently only available under NetBSD, and then only
+if both the kernel and pppd were compiled with PPP_FILTER defined.
+.TP
.B bsdcomp \fInr,nt
Request that the peer compress packets that it sends, using the
BSD-Compress scheme, with a maximum code size of \fInr\fR bits, and
.B hide-password
When logging the contents of PAP packets, this option causes pppd to
exclude the password string from the log.
+.TP
.B holdoff \fIn
Specifies how many seconds to wait before re-initiating the link after
it terminates. This option only has any effect if the \fIpersist\fR
if requested. This option has no effect unless the kernel driver
supports Predictor-1 compression.
.TP
+.B privgroup \fIgroup-name
+Allows members of group \fIgroup-name\fR to use privileged options.
+This is a privileged option. Use of this option requires care as
+there is no guarantee that members of \fIgroup-name\fR cannot use pppd
+to become root themselves. Consider it equivalent to putting the
+members of \fIgroup-name\fR in the kmem or disk group.
+.TP
.B proxyarp
Add an entry to this system's ARP [Address Resolution Protocol] table
with the IP address of the peer and the Ethernet address of this
.B welcome \fIscript
Run the executable or shell command specified by \fIscript\fR before
initiating PPP negotiation, after the connect script (if any) has
-completed. This option is privileged if the \fInoauth\fR option is
-used.
+completed. A value for this option from a privileged source cannot be
+overridden by a non-privileged user.
.TP
.B xonxoff
Use software flow control (i.e. XON/XOFF) to control the flow of data on
are only accepted in files which are under the control of the system
administrator, or if pppd is being run by root.
.PP
-The default behaviour of pppd is to allow an unauthenticated peer
-to use a given IP address if the system does not already have a
-route to that IP address already. For example, a system with a
+The default behaviour of pppd is to allow an unauthenticated peer to
+use a given IP address only if the system does not already have a
+route to that IP address. For example, a system with a
permanent connection to the wider internet will normally have a
default route, and thus all peers will have to authenticate themselves
in order to set up a connection. On such a system, the \fIauth\fR
-option should be used in /etc/ppp/options so that pppd will ask the
-peer to authenticate itself. On the other hand, a system where the
+option is the default. On the other hand, a system where the
PPP link is the only connection to the internet will not normally have
a default route, so the peer will be able to use almost any IP address
without authenticating itself.
an options file read using the \fIcall\fR option. If pppd is being
run by the root user, privileged options can be used without
restriction.
+.PP
+When opening the device, pppd uses either the invoking user's user ID
+or the root UID (that is, 0), depending on whether the device name was
+specified by the user or the system administrator. If the device name
+comes from a privileged source, that is, /etc/ppp/options or an
+options file read using the \fIcall\fR option, pppd uses full root
+privileges when opening the device. Thus, by creating an appropriate
+file under /etc/ppp/peers, the system administrator can allow users to
+establish a ppp connection via a device which they would not normally
+have permission to access. Otherwise pppd uses the invoking user's
+real UID when opening the device.
.SH AUTHENTICATION
Authentication is the process whereby one peer convinces the other of
its identity. This involves the first peer sending its name to the
projects / ppp.git / blobdiff