Networking :: Cable Modem - Losing Connection - Resolved By DHCP Request

Running 2.6.29-gentoo-r1 on a Sun Ultrasparc 10 with a Sun Happy Meal on eth0 connected directly to my cable modem. Intermittently, with a frequency between a few hours and a few days, I lose internet connectivity. Running ifconfig eth0 indicates all is well and I have a valid IP address but I cannot even ping the cable modem's management address; pings to 127.0.0.1 and eth0's IP address do get a reply but no other address I've tried does. I can 'fix' the problem by issuing

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If I check the CM logs, it appears that it has rebooted itself prior to the loss of connectivity. The strange thing is that the incoming traffic doesn't seem to be affected by this, my PSAD log is full of incoming scans even during the periods when I can't connect to the net. I suspect this is an ISP problem (they own the CM);