Cable Modem surge???

Any event that raises the voltage on the cable line can end up at the modem. As far as surges go, the cable line is no more protected than the phone line is.

Start by checking the ground point where the cable line enters the building.

The cable companies don't do as good a job with these as electricians do. If the ground rod is not installed, or the ground wire breaks any voltage surges that get on the line can get through to the modem.

Next, look at the lines from the utility pole to the modem.
Is the cable line at least 12 inches away from the electrical lines?
If not, one or both utilities need to come in and adjust the lines.

At a minimum, install a quality surge suppressor with a solid ground connection on the cable line as close to where it comes into the house as possible.

Oh, surges don't affect cable TV as much as they affect data modems because most TV setups do NOT have any connection to ground, whereas most computers are connected to ground.

Chas

You might also check building wiring for a faulty neutral leg connection. This can cause high line voltage and can be cheched with a UPS that logs power events.

aside from the others postings. I had an incident where I had my house rewired by the cable co. due to extended warrantee. When they put in the home run (line from outside box to house)they merged the cable tv signal with the internet line that kept blowing my nic cards every couple of weeks, it was a nightmare that i had to cancel due to arguments with cable co. SO has there been any rewiring? Has this been all of a sudden? Have you tried moving the gateway to another outlet in the house to determine whether the outlet is defective?