+.B /var/run/ppp\fIn\fB.pid \fR(BSD or Linux), \fB/etc/ppp/ppp\fIn\fB.pid \fR(others)
+Process-ID for pppd process on ppp interface unit \fIn\fR.
+.TP
+.B /etc/ppp/auth-up
+A program or script which is executed after the remote system
+successfully authenticates itself. It is executed with the parameters
+.IP
+\fIinterface-name peer-name user-name tty-device speed\fR
+.IP
+and with its standard input, output and error redirected to
+/dev/null. This program or script is executed with the real and
+effective user-IDs set to root, and with an empty environment.
+.TP
+.B /etc/ppp/auth-down
+A program or script which is executed when the link goes down, if
+/etc/ppp/auth-up was previously executed. It is executed in the same
+manner with the same parameters as /etc/ppp/auth-up.
+.TP
+.B /etc/ppp/ip-up
+A program or script which is executed when the link is available for
+sending and receiving IP packets (that is, IPCP has come up). It is
+executed with the parameters
+.IP
+\fIinterface-name tty-device speed local-IP-address
+remote-IP-address ipparam\fR
+.IP
+and with its standard input,
+output and error streams redirected to /dev/null.
+.IP
+This program or script is executed with the real and effective
+user-IDs set to root. This is so that it can be used to manipulate
+routes, run privileged daemons (e.g. \fIsendmail\fR), etc. Be
+careful that the contents of the /etc/ppp/ip-up and /etc/ppp/ip-down
+scripts do not compromise your system's security.
+.IP
+This program or script is executed with an empty environment, so you
+must either specify a PATH or use full pathnames.
+.TP
+.B /etc/ppp/ip-down
+A program or script which is executed when the link is no longer
+available for sending and receiving IP packets. This script can be
+used for undoing the effects of the /etc/ppp/ip-up script. It is
+invoked in the same manner and with the same parameters as the ip-up
+script, and the same security considerations apply.
+.TP
+.B /etc/ppp/ipx-up
+A program or script which is executed when the link is available for
+sending and receiving IPX packets (that is, IPXCP has come up). It is
+executed with the parameters
+.IP
+\fIinterface-name tty-device speed network-number local-IPX-node-address
+remote-IPX-node-address local-IPX-routing-protocol remote-IPX-routing-protocol
+local-IPX-router-name remote-IPX-router-name ipparam pppd-pid\fR
+.IP
+and with its standard input,
+output and error streams redirected to /dev/null.
+.br
+.IP
+The local-IPX-routing-protocol and remote-IPX-routing-protocol field
+may be one of the following:
+.IP
+NONE to indicate that there is no routing protocol
+.br
+RIP to indicate that RIP/SAP should be used
+.br
+NLSP to indicate that Novell NLSP should be used
+.br
+RIP NLSP to indicate that both RIP/SAP and NLSP should be used
+.br
+.IP
+This program or script is executed with the real and effective
+user-IDs set to root, and with an empty environment. This is so
+that it can be used to manipulate routes, run privileged daemons (e.g.
+\fIripd\fR), etc. Be careful that the contents of the /etc/ppp/ipx-up
+and /etc/ppp/ipx-down scripts do not compromise your system's
+security.
+.TP
+.B /etc/ppp/ipx-down
+A program or script which is executed when the link is no longer
+available for sending and receiving IPX packets. This script can be
+used for undoing the effects of the /etc/ppp/ipx-up script. It is
+invoked in the same manner and with the same parameters as the ipx-up
+script, and the same security considerations apply.