I have a very persistent problem with my network that I would like some help in solving. Several of the workstations periodically lose connectivity to the gateway and Internet. The outages always last less than 4 minutes, and always begin on the :X8 minute of an hour (eg. 12:08, 12:38, 5:48). When the outage is going on, pings into the workstation in question are normal, but ping out to the VPN/Firewall router or to the outside report 'host unreachable' or 'just time out. I believe that pings out to other machines on the net are OK. I have both wired servers and workstations and wireless workstations and other devices. Both wired and wireless devices exhibit the problem.
I have PRTG network monitoring running to diagnose the problem, part of a log is attached from a troubled workstation.
The network uses a Netgear 336G firewall router which handles 2 WANS but just one is in use. There are 2 VOIP devices, a Brother wireless printer, and various windows and mac workstations, and a dlink wireless router configured as an access point.
We have swapped the 336G for a replacement, installed different access points, assigned static instead of DHCP addresses, and temporarily shut down each network device in hope of isolating the problem, but nothing has worked.
4/25/2009 12:20:44 PM 104 ms 14 ms 194 ms 0 % 0 % 100 %
4/25/2009 12:20:26 PM Error Error Error Error Error 100 %
4/25/2009 12:19:46 PM Error Error Error Error Error 100 %
4/25/2009 12:18:50 PM Error Error Error Error Error 100 %
4/25/2009 12:18:17 PM Error Error Error Error Error 100 %
4/25/2009 12:17:14 PM 183 ms 15 ms 351 ms 0 % 0 % 100 %
4/25/2009 12:16:44 PM 129 ms 14 ms 243 ms 0 % 0 % 100 %
4/25/2009 12:16:14 PM 325 ms 15 ms 635 ms 0 % 0 % 100 %