At apparently decreasing intervals my 11.04 system loses WAN (outside internet) connectivity. Its hardware connection is via a wireless adapter which connects to the system via ethernet; thus the system sees an ethernet connection. When the problem occurs, there is no loss of connection to other hosts on the LAN, and another host on the LAN has WAN connectivity. Rebooting the 11.04 system cures the problem, at least for a while.
In the problem state:
ping www.apple.com --(from 11.04 system) produces no output
ping www.apple.com --(from Mac OS system on the LAN) produces normal output
ping 192.168.168.1xx --(from 11.04; IP=another host on LAN) produces normal output
ping 192.168.168.1 --(from 11.04; IP=router's LAN address) produces no output
my usual way of communicating with the 11.04 system, ssh from another host on the LAN, continues to operate normally
11.04 Chromium Browser just spins the mouse pointer when attempting to contact www.google.com
ifconfig looks OK
netstat -r looks OK
It's AS IF the router suddenly decides to block WAN access by the problem system.
Ideas or suggestions for diagnosing?