Sam Varshavchik wrote: > Aaron Konstam writes: > >> On Sat, 2010-03-06 at 15:22 -0600, Mikkel wrote: >>> On 03/06/2010 03:06 PM, Aaron Konstam wrote: >>> > > I am not using my neighbors wireless. The machine is hard-wired >>> to the >>> > router but does not use the router as a DHCP server. It did until this >>> > morning but now it does not. How does one change that behavior? >>> > Check the configuration of the router. You can also try to reset the >>> router. Outside of giving the machine a static IP address, there is >>> not much you can do on the machine. This is NOT a problem with the >>> Linux machine - it is a router problem. >>> >>> If you want to know why this is a router problem, find some good >>> documentation on how DHCP works. The machine making the request >>> responds to the first DHCP server that replies... >>> >>> Mikkel >> >> I agree with your analysis of the problem. But that leaves us with the >> following mystery.. There are 4 machines on the LAN. Why does only the >> one get a response from the providers DHCP server first? Also why this >> only occurred this morning after using the routers DHCP server for 6 >> months? > > DHCP requests are, by definition, sent to the local link broadcast > address, and can only be received by DHCP servers on the same network > segment. DHCP requests cannot cross a router or hop to a different > network segment. A DHCP server is always required to be on the same > network segment as its clients, in order to receive DHCP requests and > manage the clients. > > In other words, I'm firmly convinced that the laws of physics of our > shared universe prohibit a machine on your local LAN from being able to > obtain an IP address from some DHCP server outside of your LAN. Although > I understand that this is what you claim has happened, it is simply not > possible, according to everything I know about DHCP. Although DHCP is > not actually one of my areas of deep expertise, I'm fairly certain that > that's not how DHCP works. > I'm firmly convinced that the machine in question is visible to the ISP DHCP server, although I can't say why that would be so. > So far, looking over this thread, you've merely paraphrased what you > think is happening. You've stated what you think has happened, but in > your own words only. I don't recall you posting the actual raw, hard > data. Maybe I missed it, but if so, instead of interpreting what you > think has happened, you should actually post what's actually happening. > Without actually looking at your actual machine configuration, any > advice you receive is indistinguishable from a random guess. By > configuration I mean: > >> From your LAN machines which are configured and are working correctly: > > * The contents of your /etc/sysconfig/ifcfg-<interface> configuration files > > * The output of the "ifconfig <interface>" command > > * The output of the "route" command, with and without the -n option. > > * The contents of /etc/resolv.conf > > * The output of "grep dhclient /var/log/messages", presuming that your > most recent DHCP configuration is still logged there, and the log file > has not been rotated, since then. > > * A traceroute to some well-known site, such as www.google.com. > > Then, from your questionable host, which you believe has accomplished > the impossible feat of contacting a DHCP server on a different network > segment, the same exact stuff. The above may not necessarily be an > exclusive list, somewhat else may also suggest some other useful tidbit > to look into, but that's the bare minimum required for anyone, other > than yourself, to have any idea how your machine is configured, > network-wise. That does, also, mean that you should not mask or hide the > actual data, like replacing IP addresses or hostnames with dummy labels, > thinking that they're secret, in some way. > -- Bill Davidsen <davidsen@xxxxxxx> "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
