Mihai T. Lazarescu wrote:
In case the web/CLI interface of DSL modem/router is still responsive, you can script a reboot from the server on the LAN when fails the ping to a set of well-know always-up hosts.
Thanks very much for the suggestion, which I shall study with interest. I'm actually using a D-Link router/modem in Italy (where the problem most often arises) so hopefully your method may work.