It sounds more like the dhcp daemon on your edubuntu server is causing the problem. You should check the options to ensure the server only binds to the network card associated with the thin clients. On ubuntu the files to check are /etc/default/dhcp3-server, /etc/dhcp3-server/dhcpd.conf and possibly /etc/ltsp/dhcp.conf. You want the dhcp server to only listen on the card your thin clients are attached to. If you only have 1 network card in your edubuntu server then you should setup your existing dhcp server to serve pxe boot information (based on MAC address likely) to your thin clients and disable the dhcp server in edubuntu <div class="gmail_quote">On Wed, Sep 9, 2009 at 7:49 PM, Joseph Hartman <<a href="mailto:jlhartman@gmail.com">jlhartman@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Hey all, the Middle School has generally been without Internet since last week. Today the district guy came out and we figured out that one of my LTSP servers was screwing things up b/c the machines not connecting to the Internet were getting IP addresses of 192.168.0.___ instead of 10.36.___.___ like they should. The problem SEEMED to go away as soon as I ran up to the lab and disconnected my newly configured NAT LTSP server with firefox running as a local app (BTW, everything in the lab was working perfectly up until this little snafu). I never had a problem with the lab when firefox ran off the server. Also, I installed NAT on my own classroom LTSP server a couple of weeks ago, it's working perfectly, and there haven't been any problems at all with any computers on this side of campus, so maybe it was just a coincidence? So here are my questions: Is it possible that enabling NAT on that server has also enabled the server to start distributing IP addresses to other machines around campus that aren't directly connected to the switch in the lab? Or was this just a strange coincidence? If it was not a coincidence, is there any way to restrict the NAT server so that it only serves IP addresses to the thin clients (like restricting it to certain MAC addresses or something)? If not, what options do I have to keep firefox as a local app? Would using the <a href="https://help.ubuntu.com/community/UbuntuLTSP/ThinClientProxyRedirect" target="_blank">Thin Client Proxy Redirect howto</a> work for me? Thanks so much guys. For now the lab is down, but I'm hoping to get it back up before the week is out. Cheers -joe -- edubuntu-users mailing list <a href="mailto:edubuntu-users@lists.ubuntu.com">edubuntu-users@lists.ubuntu.com</a> Modify settings or unsubscribe at: <a href="https://lists.ubuntu.com/mailman/listinfo/edubuntu-users" target="_blank">https://lists.ubuntu.com/mailman/listinfo/edubuntu-users</a> </blockquote></div>