-while :; do
- PPTP_PROTO="$(nvram get pptp_proto)"
- [ "$PPTP_PROTO" = "static" ] || PPTP_PROTO=""
- PPTP_PROTO="${PPTP_PROTO:-dhcp}"
- IP=$(nvram get pptp_server_ip)
- USERNAME=$(nvram get ppp_username)
- PASSWORD=$(nvram get ppp_passwd)
- REDIAL=$(nvram get ppp_redialperiod)
- REDIAL=${REDIAL:+lcp-echo-interval $REDIAL}
- IDLETIME=$(nvram get ppp_idletime)
- IDLETIME=${IDLETIME:+lcp-echo-failure $IDLETIME}
- MTU=$(nvram get ppp_mtu)
- MTU=${MTU:+ mtu $MTU mru $MTU}
-
- do_ifup $PPTP_PROTO $type
-
- # hack for some buggy ISPs
- NETMASK=$(nvram get ${type}_netmask)
- IFNAME=$(nvram get pptp_ifname)
- [ -z "$NETMASK" -o -z "$IFNAME" ] || ifconfig $IFNAME netmask $NETMASK
-
- /usr/sbin/pppd nodetach \
- pty "/usr/sbin/pptp $IP --loglevel 0 --nolaunchpppd" \
- file /etc/ppp/options.pptp \
- connect /bin/true \
- usepeerdns \
- defaultroute \
- replacedefaultroute \
- linkname $type \
- user "$USERNAME" \
- password "$PASSWORD" \
- $MTU \
- $IDLETIME \
- $REDIAL
-done &
+PPTP_PROTO="$(nvram get pptp_proto)"
+[ "$PPTP_PROTO" = "static" ] || PPTP_PROTO=""
+PPTP_PROTO="${PPTP_PROTO:-dhcp}"
+IP=$(nvram get pptp_server_ip)
+USERNAME=$(nvram get ppp_username)
+PASSWORD=$(nvram get ppp_passwd)
+KEEPALIVE=$(nvram get ppp_redialperiod)
+KEEPALIVE=${KEEPALIVE:+lcp-echo-interval 10 lcp-echo-failure $KEEPALIVE}
+DEMAND=$(nvram get ppp_demand)
+case "$DEMAND" in
+ on|1|enabled)
+ DEMAND=$(nvram get ppp_idletime)
+ DEMAND=${IDLETIME:+demand idle $IDLETIME}
+ ;;
+ *) DEMAND="persist";;
+esac
+MTU=$(nvram get ppp_mtu)
+MTU=${MTU:-1452}
+
+do_ifup $PPTP_PROTO $type
+
+# hack for some buggy ISPs
+NETMASK=$(nvram get ${type}_netmask)
+IFNAME=$(nvram get ${type}_device)
+[ -z "$NETMASK" -o -z "$IFNAME" ] || ifconfig $IFNAME netmask $NETMASK
+
+/usr/sbin/pppd \
+ pty "/usr/sbin/pptp $IP --loglevel 0 --nolaunchpppd" \
+ file /etc/ppp/options.pptp \
+ connect /bin/true \
+ usepeerdns \
+ defaultroute \
+ replacedefaultroute \
+ linkname "$type" \
+ ipparam "$type" \
+ user "$USERNAME" \
+ password "$PASSWORD" \
+ mtu $MTU mru $MTU \
+ $DEMAND \
+ $KEEPALIVE