Charles Galpin wrote:
>
> I guess I haven't explained it properly, but I'm not sure If I can do any
> better than this.
>
> When the machine with the ethernet card having the mac address of
> 00:e0:98:03:9d:7b requests an IP, the dhcp server will lookup the hostname
> piglet.lhsw.com (where the dns server will look in the hosts file first
> and in this case finds it is 192.168.1.6) and assigns it to that
> machine/nic. If it cannot find this hostname's IP, it will assign one from
> the pool (so you have to either have this name in your hosts file, or be
> resolveable by dns some other way)
I understand the fixed IP deal, its the resolving some other way that I
am wondering about. Take for instance, this scenario.
Dyamically assigined ip address client named client1.
Another dynamically assigned address client named client2.
from client1 :
ping client2
Since both clients have dynamically assigned IP addresses, how does one
get name resolution to work? I can't put it into a host file since I
don't know the ipaddress and it is likly to change. Same with dns. Am
I missing a tool that talks to DNS server somehow and tells it the newly
assigned name-address pair? Is my understanding of the whole name
resolution thing inadequate and I am worrying about something that will
work magically? BTW magic is defined in this case as merely something I
don't understand :)
I suppose it makes since to have a fixed ip address for machines that
supply services that don't change regularly and most machines on the net
will use like file, database, mailservers and webservers but this sort
of defeats my vision of what could/should be possible in a perfect
world.
I appreciate your time and patience in trying to explain this to me I
feel it is above and beyond the call of duty for you to do so.
I'll dig around and see if I can find out if I am even asking a valid
question.
Bret
>
> Is this clearer, or have I misunderstood the question?
>
> charles
>
> On Thu, 27 Jan 2000, Bret Hughes wrote:
>
> > Very cool. But I still don't get how the addresses for fixed address
> > hosts get resolved.
> >
> > Bret
> >
> > Charles Galpin wrote:
> > >
> > > On Thu, 27 Jan 2000, Bret Hughes wrote:
> > >
> > > > Are you using host files for the internal machine resolution? I use a
> > > > local dns for my internal network so I don't have to change all the
> > > > hostfiles every time I add a machine to the netowork. I think there is
> > > > a DHCP tie to dns somehow I guess I need to read up.
> > >
> > > Oh, I should have said that by running a caching only name server, and
> > > telling the clients to use it, and having the search/resolve order to be
> > > the hosts file first, you get to do exactly this. You have one hosts file
> > > to maintain!. In addition, if you have clients that you would like to
> > > always get the same IP, you would let them conenct once, get their mac
> > > address and enter something like this to keep them gettign the same
> > > name/ip.
> > >
> > > host piglet {
> > > hardware ethernet 00:e0:98:03:9d:7b;
> > > fixed-address piglet.lhsw.com;
> > > }
> > >
> > > where in /etc/hosts I have
> > >
> > > 192.168.1.6 piglet piglet.lhsw.com
> > >
> > > SO eaxch client does not have to have anything (except localhost) in their
> > > hosts file. All dns queries go to your dns sevrer who has th emaster hosts
> > > file, and asks your isp for anything it doesn't know how to resolve :)
> > >
> > > hth
> > > charles
> > >
> > > > I was also thinking about the ip address conflict that I found last
> > > > night and the fact that none of the logs showed anything was wrong. The
> > > > windows box had a msg box indicating there was a conflict but nothing on
> > > > any of the linux boxes. Is there some thing I can run that will check
> > > > for ip address conflicts? I guess I could use tcpdump and check the arp
> > > > calls for a different hardware address but that seems rather hit or miss
> > > > and I am certainly not script guru.
> > >
> > > using dhcp, you would definatley know if there was a confilict (but
> > > wouldn't have any conflicts unless using a mix of static and dynamic
> > > clients)
>
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