Am Thu, 5 Mar 2015 21:19:46 +0000 schrieb Mick : > On Thursday 05 Mar 2015 18:33:23 Todd Goodman wrote: > > * Marc Joliet [150305 04:47]: > > [..SNIP..] > > > > > 1.) The NIC is brought up (some built-in Intel model). > > > > > > 2.) A DHCP client configures it. > > > > > > 3.) The network connection is lost at some point (the amount of time this > > > takes > > > > > > varies, but it can be as little as 20 minutes). > > > > > > 4.) Eventually the lease runs out and the DHCP client tries to renew it, > > > but > > > > > > gets no response. Sometimes, after many hours (at least 6), it will > > > get a DHCPACK, but that's it. One of our sysadmins says that not > > > only does the DHCP server never see the packets, but the managed > > > switch that the PC is directly attached to *also* never does (again, > > > except for when the occasional DHCPACK comes). > > > > > > 4.) Restart the network device. A reboot is not required, but it is > > > necessary > > > > > > to terminate the DHCP client. After that everything works again. > > > > > > 5.) GOTO 3. > > > > [..SNIP..] > > > > Is this a WiFi NIC? > > > > Is it possible the device is powering down? > > > > I've had lots of problems with WiFi devices powering down (both driver > > issues as well as just trying to disable the default setting of powering > > down.) > > > > Todd > > If not a WiFi, have you also tried to mirror a port at the router where the > DHCP server is running and sniff packets there? Does the router see the > DHCPREQ coming through from the client PCs? They apparently don't even reach the managed switch, which is what the PC is directly connected to (but again: the third affected PC is on a different switch). I find this very confusing :-/ (and so does our local sysadmin, or so I'm told). (I have to mention that the best I can do is relay ideas here to my boss and the aforementioned sysadmin, as I don't have access to any of the network hardware and software, save for the affected PCs. I am mostly trying to collect ideas.) -- Marc Joliet -- "People who think they know everything really annoy those of us who know we don't" - Bjarne Stroustrup