I use Kerio firewall with one of Sponge's lists, and the combination
seems to work pretty well. Which is just as well as I'm relatively new
to firewalls and not always that sure whats going on.

Tonight for several hours, I've had Kerio constantly warning me every
few minutes of:

ICMP [8] Echo Request from modem-1735.crocodile.dialup.pol.co.uk
[81.78.38.199] was blocked by rule 'Block ICMP'

Sometimes the first part of the address varies, but the
dialup.pol.co.uk part is always the same.

Anything to particularly worry about - the messages are frequent and
annoying?

Geordie2