Re: /etc/resolv.conf, /etc/ppp/resolv.conf, dhcp3-server and dnsmasq
- From: "Douglas A. Tutty" <dtutty@xxxxxxxxxxxxx>
- Date: Sun, 30 Dec 2007 21:36:12 -0500
On Sun, Dec 30, 2007 at 04:21:34PM -0700, peasthope@xxxxxxx wrote:
dt> I also have the dnsmasq package ...
My setup is almost the same. A machine I'll
call Router has dnsmasq. Another machine,
LANite, runs dhcp-client and is connected to
Router by an Ethernet crossover cable. LANite
can ping Router and Router can now ping
google.ca but the connection is not transistive;
LANite can not ping google.ca. LANite shows
the address for google.ca but gets 0 replies
from n packets. Apparently packets are not
passed through Router. So probably I must
install ipmasq or create some routing. Any
suggestions?
DNS and IP forwarding are two separate issues. Normally, however, your
DNS requests will follow the same route to the Net as other IP packets
(since DNS requests are themselves IP packets). You need to enable IP
forwarding as well as: see /etc/sysctl.conf.
dt> The magic for all this is done by resolvconf. See the man page for all
the gory details ... With eth? and ppp? interfaces coming up and going
down, the resolvconf package does a good job of keeping things working.
Appears that the design aims for deterministic
access to dns servers; but as the network becomes
more complex and dynamic, certainty is more
difficult. Being naive, I wonder whether anyone
has thought of an approach which is simpler
and more reliable and easier to troubleshoot.
For example, maintain a central list of nameservers
with a reliability index on each. PPP, dhcp,
dnsmasq & etc. could each add nameservers to the
list and adjust the reliability index. A client
needing an address would try the "best" server
first and work down. The client would be able
to adjust the reliability index according to the
response it gets from the server.
Yes, but, at any given point in time, there should only be one
"upstream" route and the upstream DNS servers should be somewhere along
that route. Networking is by necessity deterministic. Once things get
complicated enough that you have multiple routes to this that and the
other thing with multiple DNS servers, you're at the level of an ISP or
at least a datacentre with redundant connections and all the baggage
that entails. At that level, you wouldn't trust any pre-packaged
solution. You would figure out what commands are required for each
possible transition and write you own scripts.
Someone who does run a datacentre is now going to call in and tell the
world what a fool I am; that they use the WizzBangUltra Universal
Configurator. Go figure.
dt> ... connect to the internet with ppp at the same
time [as with eth], default routing and dns servers
will not change and life gets interesting.
Ref. paragraph above.
Doug.
--
To UNSUBSCRIBE, email to debian-user-REQUEST@xxxxxxxxxxxxxxxx
with a subject of "unsubscribe". Trouble? Contact listmaster@xxxxxxxxxxxxxxxx
- References:
- Prev by Date: Re: OOo window in fluxbox
- Next by Date: Re: debian how-to
- Previous by thread: Re: /etc/resolv.conf, /etc/ppp/resolv.conf, dhcp3-server and dnsmasq
- Next by thread: Tunnel between two IPv6 islands in an IPv4 ocean?
- Index(es):
Relevant Pages
|
|
