[Pacemaker] How to flush the arp cache of a router?

[georg at riseup.net]

He all,

I'm using Debian Stable and corosync/pacemaker/DRBD with Asterisk in a
master/slave-setup.
I get calls routed from my carrier to an ip in a private net. I'm using a
Cisco 876 as the router.

As the ressource agent for managing a virtual ip I'm using IpAddr2, which
should do arp broadcast when bringing up the ip (as far as I read).
However, in my case this doesn't work.
I then had a look at SendArp, but read, that one shouldn't use this in
conjunction with IpAddr2. Anyway, this didn't work also.

In the end I tried to use arping, which works great, but I found no way to
execute it from the cluster automatically. I tried to put it into a file
and made this executable, and used lsb: to call it (which didn't work).
Then I googled for hours to find out, how to call scripts from within crm,
but had no success...

Could someone point me into the right direction?

Thanks,
Georg