Данные конфиги для подключения к анлиму от интерсвязи.

Получение маршрутов по DHCP:

/etc/dhclient.conf:

timeout 60;
retry 60;
reboot 10;
select-timeout 5;
initial-interval 2;

interface "rl1" {
send dhcp-lease-time 3600;
request subnet-mask, broadcast-address, time-offset, routers, domain-name, domain-name-servers, host-name, static-routes, classless-routes;
require subnet-mask, domain-name-servers, routers;
}

После этого все работает хорошо, но у меня не устанавливался маршрут по умолчанию. Для этого подправим /sbin/dhclient-script.

add_new_routes() {
...
if [ -n "$new_classless_routes" ]; then
fill_classless_routes "$new_classless_routes"
$LOGGER "New Classless Static Routes ($interface): $classless_routes"
set $classless_routes
while [ $# -gt 1 ]; do
if [ "0.0.0.0" = "$2" ]; then
route add "$1" -iface "$interface"
else
route add "$1" "$2"
fi
shift; shift
done
#return - комментируем
fi
...
}

Настраиваем mpd5.

mpd.conf:

pptp_client:
create bundle static B1
set iface up-script /usr/local/etc/mpd5/mpd_up.sh
set iface down-script /usr/local/etc/mpd5/mpd_down.sh
create link static L1 pptp
set link action bundle B1
set auth authname "user"
set auth password "pass"
set link max-redial 0
set link mtu 1500
set link keep-alive 20 75
set pptp peer unlim.is74.ru
set pptp disable windowing
open

mpd_up.sh:

#!/bin/sh
PREFIX=/usr/local
export PATH=/sbin:/bin:/usr/bin:/usr/sbin:${PREFIX}/bin:${PREFIX}/sbin
netstat -rn | grep '^default' | awk '{print $2}' > /tmp/defaultroute
for serverip in `host unlim | awk '{print $4}'`
do
route add -host $serverip `cat /tmp/defaultroute`
done
route change default $4

mpd_down.sh:

#!/bin/sh
PREFIX=/usr/local
export PATH=/sbin:/bin:/usr/bin:/usr/sbin:${PREFIX}/bin:${PREFIX}/sbin

route change default `cat /tmp/defaultroute`
for serverip in `host unlim | awk '{print $4}'`
do
route delete -host $serverip
done