[CentOS] making a route sticky

Is it possible to have a route stick in the kernel, even if device it points to
goes to roller coaster up and down drive.

For example.  I have an ADSL modem and am doing VPN over it.  There's a route
needed for VPN added like this:

ip route add 192.168.1.0/24 via 1.2.3.4 src 192.168.2.1

There are two problems with it:

a) if ADSL link is down when above command is executed, the route command will
fail (ppp0 is down, so there's no 1.2.3.4)

b) if ADSL link is up when above command is executed, but it goes down (and up
again) later, the route is removed from kernel routing tables

So, if there are any problems with ADSL link, I need to manually reset my VPN
setup.

I could write some monitoring script (and call it from cron) that would check if
route is present and attempt to readd it if needed, but I'd rather be able to
have the route either sticky (not removed when interface goes down) or
automatically reenabled by the kernel when interface goes up again.

Thanks,
Aleksandar Milivojevic

----------------------------------------------------------------
This message was sent using IMP, the Internet Messaging Program.