On Sun, 27 Dec 2009, Carlos Konstanski wrote: > Date: Sun, 27 Dec 2009 11:39:24 -0700 (MST) > From: Carlos Konstanski <[email protected]> > Reply-To: "General Linux/UNIX discussion and help; civil and on-topic" > <[email protected]> > To: "General Linux/UNIX discussion and help; civil and on-topic" > <[email protected]> > Subject: Re: [PLUG] resolve.conf file > > On Sun, 27 Dec 2009, Denis Heidtmann wrote: > >> Date: Sun, 27 Dec 2009 10:10:59 -0800 >> From: Denis Heidtmann <[email protected]> >> Reply-To: "General Linux/UNIX discussion and help; civil and on-topic" >> <[email protected]> >> To: "General Linux/UNIX discussion and help, civil and on-topic" >> <[email protected]> >> Subject: [PLUG] resolve.conf file >> >> I mentioned earlier that I was having trouble with a new dsl modem's >> behavior as a dns server. That has been resolved by avoiding dhcp. >> This was accomplished with the help of a visiting geek (my son). >> Resolveconf was installed; dns addresses set statically, >> >> As best as I can determine, everything is working fine. But I seek >> some understanding. The resolv.conf contains some entries which make >> no sense to me. The visiting geek is no longer interested in these >> questions, as it is no longer broken. So I appeal to you. >> >> resolv.conf: >> >> # Dynamic resolv.conf(5) file for glibc resolver(3) generated by >> resolvconf(8) >> # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN >> nameserver 192.168.0.1 >> nameserver 69.64.224.67 >> nameserver 69.64.224.66 >> search domain.actdsltmp >> >> I expect that the nameserver 192.168.0.1 entry is left over from >> earlier dhcp responses. (Visiting geek's Debian machine has only the >> two valid nameserver entries in his file--he had not run a dhcp >> client.) Why does it persist in this file? And why does it not break >> dns searches occasionally? If I run dig repeatedly, only the >> 69.64.224.67 address seems to get used. If I force use of >> 192.168.0.1, it fails, as expected. >> >> What does "search domain.actdsltmp" do? Is domain.actdsltmp a valid name? >> >> Should I attempt to clean up this file? If I should, how might that be done? >> >> Thanks for any education you can throw my way. >> >> -Denis > > 192.168.0.1 is most likely the IP address of your DSL router. I never > used resolvconf, but if it's writing this file, then I'll bet that > there is some sort of DNS server running on the router. Run the > following command from a root shell (it will take a long time to run): > > nmap -sU 192.168.0.1 > > If you see UDP port 53 listed as open, then there is a DNS server > running on the router. (If you see port 68, that's the DHCP server.) > If this is true, it would be in your best interests to get it working > properly, and use it instead of going directly to the ISP DNS > servers. The local DNS server should be doing lookups on behalf of all > users on your LAN, and caching the results for faster speed and less > internet chatter. > > The "search" line is for when you attempt to resolve a > non-fully-qualified hostname. For instance, my local domain is > pippiandcarlos.com, and this is reflected in my resolv.conf file as > "search pippiandcarlos.com". If I try to "ping ns", it will be > converted to "ping ns.pippiandcarlos.com". > > I hate to be a party pooper, but I still feel that using resolvconf > and static IPs is a bandaid that will continue to peel off when > wet. The right thing to do is to get your own DNS and DHCP servers > (the ones on the DSL router) working properly. Of course these DSL > modems are notoriously crappy, and it is quite possible that fiddling > with its configuration will have no effect. That's why I use cable and > my own linux box as a router/firewall. Cable modems do not contain > router/firewalls; they simply pass the connection through. The last > DSL modem I had was an Actiontek which did not respond to any of my > attempts to configure it. Qwest refused to replace it. They told me I > could buy my own. Customer exits stage. > > Carlos
Correction: DHCP is on UDP port 67, not 68. Carlos _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
