help setting a home network

Hello,

I want to set up a router that connects to a cable modem and services
a private lan. I've got most things figured out, except one: The dns
configuration on the private lan.

The router gets its dns from the cable modem (through dhcp). But how
can i propogate this to the machines on the lan? The router is also a
dhcp server, and I know I can put the domain-name-servers option in
dhcpd.conf. However, this means the IPs will be static, and my ISP
changes them sometimes. So I want either to have the dhcp server
pickup the IPs dynamically somehow, or have the machines on the lan do
it.

Thanx,
Ittay

(E-Mail Removed) (Ittay Freiman) wrote in message news:<(E-Mail Removed) m>...
> Hello,
>
> I want to set up a router that connects to a cable modem and services
> a private lan. I've got most things figured out, except one: The dns
> configuration on the private lan.

That's exactly what our router software does, dhcp relays.

>
> The router gets its dns from the cable modem (through dhcp). But how
> can i propogate this to the machines on the lan? The router is also a
> dhcp server, and I know I can put the domain-name-servers option in
> dhcpd.conf. However, this means the IPs will be static, and my ISP
> changes them sometimes. So I want either to have the dhcp server
> pickup the IPs dynamically somehow, or have the machines on the lan do
> it.

The local IP should be static and masqueraded.

>
> Thanx,
> Ittay

IDE Compact Flash Drive
http://ide-cf.info-for.us

On 1 Sep 2003 04:04:58 -0700
(E-Mail Removed) (Ittay Freiman) wrote:

> Hello,
>
> I want to set up a router that connects to a cable modem and services
> a private lan. I've got most things figured out, except one: The dns
> configuration on the private lan.

Which router? Mine (Linksys) Hands out dhcp (192.168.1.1xx) to the
computers. The computers all have 192.168.1.1 (The router) as the
default gateway.

> The router gets its dns from the cable modem (through dhcp). But how
> can i propogate this to the machines on the lan? The router is also a
> dhcp server, and I know I can put the domain-name-servers option in
> dhcpd.conf. However, this means the IPs will be static, and my ISP
> changes them sometimes. So I want either to have the dhcp server
> pickup the IPs dynamically somehow, or have the machines on the lan do
> it.

You don't propagate it internally. The router has an ip address, given
out by you're cable company. If your router does NAT, you're all set.

I think you are misusing terms. Go to http://tldp.org and look around
for networking/NAT howtos.
--
-johann koenig
Now Playing: Aimee Mann - I've Had It : KCRW Rare On Air (Vol. 2)
Today is Prickle-Prickle, the 25th day of Bureaucracy in the YOLD 3169
My public pgp key: http://mental-graffiti.com/pgp/johannkoenig.pgp

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I must have written this message very badly, as I got replies that
were unrelevant. Here it is, rewritten:

I have a computer setup as a gateway. It gets its external IP through
dhcp from the cable company. It also gets IPs for DNS servers. I also
have several computers set up as a private LAN. Each of them should
also get the IPs for the DNS servers. There are several ways I know of
for doing that, I like neither:
1. put the IPs statically in /etc/resolv.conf in each machine.
2. make the gateway be a dhcp server and configure it to give the IPs
of the DNS. these IPs will also be written statically in the dhcp.conf
file.
3. install a DNS server (or DNS caching server) in the gateway.

All of these options mean that the DNS IPs are static, hard-coded in
some configuration file. But since I get them dynamically from my ISP,
I want to provide them dynamically to the machines in my LAN. How can
I do that?

Thank you,
Ittay

Johann Koenig <(E-Mail Removed)> wrote in message
news:<(E-Mail Removed)>.. .
> On 1 Sep 2003 04:04:58 -0700
> (E-Mail Removed) (Ittay Freiman) wrote:
>
> > Hello,
> >
> > I want to set up a router that connects to a cable modem and services
> > a private lan. I've got most things figured out, except one: The dns
> > configuration on the private lan.
>
> Which router? Mine (Linksys) Hands out dhcp (192.168.1.1xx) to the
> computers. The computers all have 192.168.1.1 (The router) as the
> default gateway.
>
> > The router gets its dns from the cable modem (through dhcp). But how
> > can i propogate this to the machines on the lan? The router is also a
> > dhcp server, and I know I can put the domain-name-servers option in
> > dhcpd.conf. However, this means the IPs will be static, and my ISP
> > changes them sometimes. So I want either to have the dhcp server
> > pickup the IPs dynamically somehow, or have the machines on the lan do
> > it.
>
> You don't propagate it internally. The router has an ip address, given
> out by you're cable company. If your router does NAT, you're all set.
>
> I think you are misusing terms. Go to http://tldp.org and look around
> for networking/NAT howtos.

Ittay Freiman wrote:

> Hello,
>
> I want to set up a router that connects to a cable modem and services
> a private lan. I've got most things figured out, except one: The dns
> configuration on the private lan.
>
> The router gets its dns from the cable modem (through dhcp). But how
> can i propogate this to the machines on the lan? The router is also a
> dhcp server, and I know I can put the domain-name-servers option in
> dhcpd.conf. However, this means the IPs will be static, and my ISP
> changes them sometimes. So I want either to have the dhcp server
> pickup the IPs dynamically somehow, or have the machines on the lan do
> it.


The IPs on your local lan have nothing to do with the IP assigned by your
ISP. You can configure your local network to have static IPs and use the
hosts file for name resolution.


--

Fundamentalism is fundamentally wrong.

To reply to this message, replace everything to the left of "@" with
james.knott.

James Knott wrote:
> Ittay Freiman wrote:
>
>
>>Hello,
>>
>>I want to set up a router that connects to a cable modem and services
>>a private lan. I've got most things figured out, except one: The dns
>>configuration on the private lan.
>>
>>The router gets its dns from the cable modem (through dhcp). But how
>>can i propogate this to the machines on the lan? The router is also a
>>dhcp server, and I know I can put the domain-name-servers option in
>>dhcpd.conf. However, this means the IPs will be static, and my ISP
>>changes them sometimes. So I want either to have the dhcp server
>>pickup the IPs dynamically somehow, or have the machines on the lan do
>>it.
>
>
>
> The IPs on your local lan have nothing to do with the IP assigned by your
> ISP. You can configure your local network to have static IPs and use the
> hosts file for name resolution.
>
>

run dnsmasq on the router.


That way ur router is the internal dns server.

bal.

In article <(E-Mail Removed)> , Ittay
Freiman <(E-Mail Removed)> writes
>I have a computer setup as a gateway. It gets its external IP through
>dhcp from the cable company. It also gets IPs for DNS servers.

OK, normal setup.

>I also
>have several computers set up as a private LAN. Each of them should
>also get the IPs for the DNS servers. There are several ways I know of
>for doing that, I like neither:
>1. put the IPs statically in /etc/resolv.conf in each machine.

You could, but it seems silly when the gateway gets them by DHCP

>2. make the gateway be a dhcp server and configure it to give the IPs
>of the DNS. these IPs will also be written statically in the dhcp.conf
>file.

Is it necessary to make them static there? Couldn't dhcpd be set to send
the ones it got from your ISP?

>3. install a DNS server (or DNS caching server) in the gateway.

That seems an eminently sensible approach to me. Indeed it's what I do.
That said, bind tends to use lots of top level name servers, rather than
the ISP's one.
>
>All of these options mean that the DNS IPs are static, hard-coded in
>some configuration file.

No, the last one doesn't. Or shouldn't - the DNS server will obtain the
latest DNS addresses automatically and the other machines only need to
know your local DNS

--
Rob Pearce

The "from" must be wrong, nothing that helpful ever comes from the TAN team!

On 1 Sep 2003 22:02:32 -0700
(E-Mail Removed) (Ittay Freiman) wrote:

> I have a computer setup as a gateway. It gets its external IP through
> dhcp from the cable company. It also gets IPs for DNS servers. I also
> have several computers set up as a private LAN. Each of them should
> also get the IPs for the DNS servers. There are several ways I know of
> for doing that, I like neither:
> 1. put the IPs statically in /etc/resolv.conf in each machine.
> 2. make the gateway be a dhcp server and configure it to give the IPs
> of the DNS. these IPs will also be written statically in the dhcp.conf
> file.
> 3. install a DNS server (or DNS caching server) in the gateway.
>
> All of these options mean that the DNS IPs are static, hard-coded in
> some configuration file. But since I get them dynamically from my ISP,
> I want to provide them dynamically to the machines in my LAN. How can
> I do that?

My /etc/resolv.conf:
jkoenig@note:~$ cat /etc/resolv.conf
nameserver 192.168.1.1
jkoenig@note:~$

I'm not sure how this would change if your router is a Linux box, not a
Linksys Router. Here is how I get nameserver in resolv.conf:
jkoenig@note:~$ cat /etc/network/interfaces
<snip comments and loopback interface>
auto eth0
iface eth0 inet static
address 192.168.1.3
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.1
jkoenig@note:~$

I don't know if this works because the router does some sort of special
DNS, or because of the inherent action of 'nameserver.' I think it works
like thus:
note (my computer) sends request to router
router looks it up
router returns it to note

I'd test it by setting 'gateway' to another one of my computers and
trying some name resolution, but I'm pretty tired right now.
--
-johann koenig
Now Playing: Rancid - 1998 : Punk-O-Rama (Vol. 4)
Today is Setting Orange, the 26th day of Bureaucracy in the YOLD 3169
My public pgp key: http://mental-graffiti.com/pgp/johannkoenig.pgp

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