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At Gordon's suggestion, did a bunch of tests of check_router script (which should have fixed this problem by itself). It has a long time-out of 3--5minutes, but did work as expected with the LAN cable unplugged. Thus, don't know why this script didn't fix this problem in the first placeWe next want to run a test by unplugging the 3G modem, but ran out of power on our laptop. We'll do this test tomorrow on the spare in the base.