+.B noipdefault
+Disables the default behaviour when no local IP address is specified,
+which is to determine (if possible) the local IP address from the
+hostname. With this option, the peer will have to supply the local IP
+address during IPCP negotiation (unless it specified explicitly on the
+command line or in an options file).
+.TP
+.B lcp-echo-interval \fI<n>
+If this option is given, \fIpppd\fR will send an LCP echo-request
+frame to the peer every \fIn\fR seconds. Under Linux, the
+echo-request is sent when no packets have been received from the peer
+for \fIn\fR seconds. Normally the peer should respond to the
+echo-request by sending an echo-reply. This option can be used with
+the \fIlcp-echo-failure\fR option to detect that the peer is no longer
+connected.
+.TP
+.B lcp-echo-failure \fI<n>
+If this option is given, \fIpppd\fR will presume the peer to be dead
+if \fIn\fR LCP echo-requests are sent without receiving a valid LCP
+echo-reply. If this happens, \fIpppd\fR will terminate the
+connection. Use of this option requires a non-zero value for the
+\fIlcp-echo-interval\fR parameter. This option can be used to enable
+\fIpppd\fR to terminate after the physical connection has been broken
+(e.g., the modem has hung up) in situations where no hardware modem
+control lines are available.
+.TP