On 2010-07-11 02:18, Lord Devi wrote:
Hello.
I have a fairly simple home network, to which I have recently added a
second subnet to for my virtual machines. While my primary DNS/DHCP
server is a Dnsmasq instance running on my DD-WRT router, my second
subnet is hosted from a machine inside the Lan. On that machine I run
multiple virtual machines, and desire to serve DHCP and DNS information
to them from a second Dnsmasq instance running on the first virtual
machine. However I've managed to confuse myself greatly on this subject
going through the Dnsmasq archives. So I will simply try to state my
intentions and current configuration as clearly as possible, and hope
someone can clarify some things for me.
My current network resembles the following:
Subnet A:
Network Range: *192.168.1.0/24 <http://192.168.1.0/24>*
/Gateway 1A/: *192.168.1.1/255.255.255.0
<http://192.168.1.1/255.255.255.0>* (This is my DD-WRT router which
provides internet access)
Gateway Interfaces:
/br0/: *192.168.1.1/255.255.255.0 <http://192.168.1.1/255.255.255.0>*
/vlan1/: *70.76.84.224/255.255.252.0 <http://70.76.84.224/255.255.252.0>*
DNS / DHCP (Dnsmasq): *192.168.1.1* (Both served from the above DD-WRT
router)
LAN Domain: tec.lan
Example /Host 1A/: *perpetrator.tec.lan - 192.168.1.10/255.255.255.0
<http://192.168.1.10/255.255.255.0>*
Example /Host 2A/: *rapine.tec.lan - 192.168.1.12/255.255.255.0
<http://192.168.1.12/255.255.255.0>*
Subnet B:
Network Range: *192.168.2.0/24 <http://192.168.2.0/24>*
/Gateway 1B/: *192.168.2.1/255.255.255.0
<http://192.168.2.1/255.255.255.0>* (This is my internal machine which
hosts my virtual machines)
Gateway Interfaces:
/eth0/: *192.168.1.11/255.255.255.0 <http://192.168.1.11/255.255.255.0>*
/eth1/: *192.168.2.1/255.255.255.0 <http://192.168.2.1/255.255.255.0>
*DNS / DHCP (Dnsmasq): *192.168.2.2* (This is the very first virtual
machine hosted on Gateway 1B)
LAN Domain: tec.lan
Example /Host 1B/: *ubuntu-01.tec.lan - 192.168.2.10/255.255.255.0
<http://192.168.2.10/255.255.255.0>*
Example /Host 2B/: *ubuntu-02.tec.lan - 192.168.2.11/255.255.255.0
<http://192.168.2.11/255.255.255.0>
*
First off I have to say that working with multiple subnets in such a
manner is a new task for me, and I may indeed be going about things
improperly in relation to Dnsmasq here. But what I have been trying to
do up until now is have client machines on Subnet B use 192.168.2.2 as
their DHCP and DNS server, and have it so when they need DNS information
for either Subnet A, OR the Internet itself, they would then pass
queries on to the Dnsmasq server on 192.168.1.1. In effect, sort of
chaining requests.. I have attempted things like manually adding both
192.168.1.1 and 192.168.2.2 to /etc/resolv.conf on guest machines hosted
on Subnet B, but have had mixed results with that.For instance if I list
192.168.2.2 FIRST in /etc/resolv.conf on those machines they can get DNS
queries for ubuntu-01.tec.lan just fine say, but when I ask them about
rapine.tec.lan or google.ca <http://google.ca>, they do not get
resolved. (I had thought that if a domain to be resolved was not found
on the first nameserver inside resolv.conf, they would then ask the
second in the list and THEN get the results needed. But it does not
appear to work this way.)
So then I thought maybe, clients on Subnet A could be configured to ask
ONLY 192.168.2.2 for DNS information, and then the Dnsmasq server on
192.168.2.2 would then itself know to ask 192.168.1.1 for DNS
information for which it itself did not know about. So to that end, I
appended the following line to my dnsmasq.conf file on 192.168.2.2
<http://192.168.2.2>:
server=192.168.1.1
This seems to allow machines on Subnet B to be able to contact
rapine.tec.lan and google.ca <http://google.ca> just fine. However when
I tried to add:
server=192.168.2.2
to Gateway 1A: to try to get my Dnsmasq on 192.168.1.0/24
<http://192.168.1.0/24> to ask 192.168.2.2 about machines on the
192.168.2.0/24 <http://192.168.2.0/24> subnet, all my Subnet A client
machines then started to have problems and delays when trying to resolv
information for the Internet. So obviously I was doing something wrong..
At this point I am kind of stuck. I fear I have confused myself greatly
and am having great difficulties figuring this one out.
Even if there is an option I can add to my Dnsmasq server on Gateway 1A
to achieve my ends, I would still be left with a sense of unease that I
may not be doing things correctly in the first place. If someone could
both help me configure this so that machines on both Subnet A and B can
resolv each other fine, AND help instruct me a bit on the "best
practises" of such a configuration I would be very appreciative!!
Following I have pasted the contents of my relevant dnsmasq.conf files
to demonstrate further what it is I am CURRENTLY doing.
Subnet A's relevant dnsmasq.conf on 192.168.1.1 <http://192.168.1.1>:
interface=br0
resolv-file=/tmp/resolv.dnsmasq
domain=tec.lan
dhcp-leasefile=/tmp/dnsmasq.leases
dhcp-lease-max=54
dhcp-option=lan,3,192.168.1.1
dhcp-authoritative
dhcp-range=lan,192.168.1.100,192.168.1.149,255.255.255.0,1440m
Subnet B's relevant dnsmasq.conf on 192.168.2.2 <http://192.168.2.2>:
interface=eth0
domain=tec.lan
dhcp-leasefile=/tmp/dnsmasq.leases
dhcp-lease-max=54
dhcp-option=option:router,192.168.2.1
dhcp-authoritative
dhcp-range=lan,192.168.2.100,192.168.2.149,255.255.255.0,1440m
server=192.168.1.1
expand-hosts
(An example of the sort of things I am uncertain about, is how you might
notice I have "dhcp-authoritative" set on both of my Dnsmasq servers. I
have a feeling this is wrong, and even IF I was getting the network DNS
resolutions I am looking for, am not sure if that is correct.)
Please help unconfuse me!!
Best regards,
Casey Quibell.
p.s. If there is any further information I can provide to help in
diagnosing my issue, please ask!
If I were you I would not run dnsmasq on Gateway 1B at all. I would use a DHCP
relay instead to forward DHCP requests from subnet B to dnsmasq running on the
gateway 1A. That way there would be only one DNS server for both networks
without configuration trickery necessary.
