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I have an (allegedly) 15mbps cable connection from Comcast with a pretty standard setup - cable modem plugged in to Netgear router, which serves one PC via an ethernet cable and several laptops via wireless.
The problem is that, on the desktop only (running Vista), DNS frequently fails. It will work fine for half an hour or so, and then I'll start getting DNS lookup errors, even on sites I've been actively browsing - but not all sites at once, some still work. If I run a command shell as an admin and run ipconfig /flushdns then everything starts working fine again for another period of time. But it is extremely annoying.
All the settings, on both the PC and the router, have "Automatically acquire DNS Server address from ISP" set. And it seems to work fine on all the other computers on the network.
Very puzzled. Any help would be appreciated, I just don't know networking that well.
@bortzmeyer Really? I shouldn't be surprised and for me it's irrelevant anyway as I have a /29 and my own authoritative DNS server (and reverse PTR delegation) but what you say is a good thing to know (though it's also shameful they do that). I’m not sure I have a problem with NXDOMAIN to advertisements but I suppose that could be a problem to some (though why I don't know esp with malvertisements). – Pryftan – 2018-10-23T13:10:52.043
2But it will create many other problems: for instance, OpenDNS name servers lie, they rewrite "No such domain" answers to the IP address of an advertisment Web site, they block some domains, they sell data about your queries, etc. – bortzmeyer – 2009-07-21T09:51:37.773