top posting - iihh ugly ;-p
well, it's the netfilter code from the kernel instructed by an
iptables rule, that spits out that message.
most likely this is a message informing you about a blocked packet.
the question is: who/what set this iptables rule to tell the kernel to
discard such packets?
my cristal ball is currently somehow foggy, so I can't tell.
maybe you know what firewall frontend you are using?
what to do?
well - to prohibit logging of those packets in the short term a rule
like this may do the job:
iptables -I INPUT -i eth1 -s 192.168.1.1 -p icmp --icmp-type 8 -j DROP
for the long term:
learn how to configure your firewall frontend or iptables.
but it's you modem/router right?
so it might just check if you online. so it could be a 'good packet',
which you might want to accept. - same thing as above just with the
ACCEPT target.
best regards
Mart