/etc/resolv.conf changes

[Aaron Konstam]

Ok, I am posting in the top since I made such a boo boo. This is the
second or third time I made this transposition. I did not mean DNS
servers but DHCP servers. It must be an age thing
On Tue, 2008-03-25 at 11:29 -0400, Matthew Saltzman wrote:
> On Tue, 2008-03-25 at 10:24 -0600, Aaron Konstam wrote:
> > On Mon, 2008-03-24 at 17:58 -0400, Matthew Saltzman wrote:
> > > On Mon, 2008-03-24 at 16:09 -0600, Aaron Konstam wrote:
> > > 
> > > > You really can't edit /etc/resolv.conf when you are using a DNS server.
> > > > When you are connected to the network it is the DNS nameserver that sets
> > > > up the resolv.conf file. In the first case above:
> > > 
> > > This isn't quite correct.  
> > > 
> > > /etc/resolv.conf contains the IP addresses of your DNS servers.
> > This is a semantic argument. We are talking about wireless. Until you
> > connect to the wireless router's AP the resolve.conf computer has no
> > idea about the name of your DNS server. The router supplies that form
> > the DNS server.
> 
> Not semantics at all.  DNS servers don't self-report--and in particular,
> they don't reach out and edit clients' /etc/resolv.conf files.  DHCP
> servers can provide DNS server information to clients, or not.  If it is
> offered, DHCP clients can accept the information (and place it
> in /etc/resolv.conf), or not.  For static IP addresses and for DHCP
> clients that don't get DNS info from the server, /etc/resolv.conf
> contents must be created manually.  
> 
> Clients are not required to use the local network's suggestions for DNS
> servers--they can use any servers they can reach by IP address.  (For
> example, clients can run their own caching nameservers, and just use
> 127.0.0.1 as the DNS server IP.)
> 
> Some wireless routers will get their own IP addresses by DHCP from, say,
> a DSL modem (which may in turn get its IP address and DNS server info
> from the ISP).  As a DHCP server, the modem may provide DNS server
> information to the router.  As a DHCP client, the router may accept that
> information or the user may set it (and/or the router's IP address)
> manually.
> 
> Having the router get DNS from the modem and provide it in turn to
> clients is a pretty seamless way to go, and it is quite common
> (particularly in home networks), but it is by no means required.
> 
> > > 
> > > If you connect to your network with a DHCP server, that server provides
> > > your IP address and it *may* provide information about DNS servers,
> > > which your dhcp client will put in /etc/resolv.conf.  It also may not,
> > > or you may decline to use the provided information.  Or you may connect
> > > statically.  In that case, you need to hand-edit /etc/resolv.conf or use
> > > system-config-network to set static DNS servers.
> > > 
> > > > > # generated by NetworkManager, do not edit!
> > > > > ; Use a local caching nameserver controlled by NetworkManager
> > > > > nameserver 127.0.0.1
> > > > 
> > > > you has not yet made a connection to the internet.
> > > 
> > > Network manager uses a DHCP client to get your DNS info and places it
> > > in /etc/resolv.conf.  If you decline to use that information, you
> > > probably have installed a caching nameserver.  In that case, its IP
> > > address is 127.0.0.1
> 
> -- 
>                 Matthew Saltzman
> 
> Clemson University Math Sciences
> mjs AT clemson DOT edu
> http://www.math.clemson.edu/~mjs
> 
--
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You work very hard. Don't try to think as well.
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Aaron Konstam telephone: (210) 656-0355 e-mail: akonstam at sbcglobal.net