How to make two different subnets from existing single network?

I have my local LAN (172.16.1.x) connecting all Computers to Router to
the Cable modem for Internet access. I would like to keep half of my
computers in different subnet (172.16.35.x), how can I do that?. thanks
in advance.

On 2005-04-20, (E-Mail Removed) <(E-Mail Removed)> wrote:
> the Cable modem for Internet access. I would like to keep half of my
> computers in different subnet (172.16.35.x), how can I do that?.

Give them IPs in that subnet. And exactly why you want to do so?
Davide

--
I used to be convinced that MicroSquish shipped crap becase they simply
didn't give a flying fuck as long as the sheep kept buying their shit. Now,
I'm convinced that MicroSquish really does ship the best products they are
capable of writing, and *that's* tragic. --jcr

(E-Mail Removed) wrote:
> I have my local LAN (172.16.1.x) connecting all Computers to Router to
> the Cable modem for Internet access. I would like to keep half of my
> computers in different subnet (172.16.35.x), how can I do that?. thanks
> in advance.
>
do you want these ip's automatically assigned?

any pc can speak to any other pc configured with an ip in the same range
so any user can just change their ip to another on a different subnet to
become part of that

pretty useless... really

if you want to block one subnet access from something, better to use a
firewall

changing the subnet is kinda like changing the workgroup name on windows

Yes, I want my IP's automatically assigned, basicaly each subnet has to
talk to different subnet through gateway (172.16.35.1 is gateway for
172.16.35.x subnet, similarly 172.16.1.1 is gateway for other subnet).
Basically, I would like to keep some machines for testing purpose in
lab. This way lab can be separated from administration dept. is it
doable?. but for maintaing two different subnets, do I need extra
router?. thanks.

santa19992...@yahoo.com wrote:
> Yes, I want my IP's automatically assigned, ...

Assigned by dhcpd, I assume, but where does it reside? Gateway
machine?

> ... basicaly each subnet has to
> talk to different subnet through gateway (172.16.35.1 is gateway for
> 172.16.35.x subnet, similarly 172.16.1.1 is gateway for other
subnet).
> Basically, I would like to keep some machines for testing purpose in
> lab. This way lab can be separated from administration dept. is it
> doable?. but for maintaing two different subnets, do I need extra
> router?. thanks.

Afaict, all you need is another nic in gateway/router:

-- one nic to CM
-- one nic on the 172.16.1.0 subnet
-- one nic on the 172.16.35.0 subnet
-- an additional switch for new subnet?

If the CM is to provide IPs for clients, this might or might not work.

If dhcpd is to run on gateway/router it is doable but perhaps not very
wise. I don't like the idea of running this sort of service on a
gateway/firewall machine.

If you have machines on each subnet that can service dhcp requests,
that would be best.

If this sort of "physical" subnet segregation is not feasible, then
you'll have to use policy routing and some pretty nimble dhcpd
configuration.

If policy routing seems too much of a hassle, you could use a vlan
switch (Linux box?) to set up vlans; one vlan for admin dept. and one
for lab. Setting up dhcpd could be a hassle depending on the switch
and placement of dhcpd server.

In any case, if I understand your situation, you have several ways you
could make this work. Installing a new physical subnet (extra nic and
switch) is probably the easiest.

good luck,
prg

Well, you can have a server with 2 NICs in it, doing routing.
Also, you can configure dhcpd (the dhcpd daemon) to provide a different
IP address for clients on each NIC.

You would of course configure each nic with an ip in its range.

Then set up dhcpd (see the man) or use a web interface such as webmin,
or your linux distros config util (i know suse's is "yast")..

And whalla, 2 subnets.

Further then... in dhcp you can give a default gateway and dns to hand
out when clients receive their ips. You would set the gateway to the ip
for the nic on that subnet (of course, each nic you can run to a
switch/hub, and from there to pcs on the diff subnets)

Then all you have to do is add the routes

Ive done this, but it was confusing

route -n

lists the current route
now, as I have it

route add -net 192.168.0.1/24 gw MMM

NO MAN
I am talkin crap.

You dont need to set up any routes
Just enable IP forwarding / masquerading or something and they'll work
haha dont believe this, better let someone who knows tell you whats up
further...

Sorry I cant be of more help... Ciao

route add -net 0.0.0.0 gw [default route]
adds the default route, though

But youre gonna have to put this in a boot script
Most linux's have got something in place thats gonna screw you around if
you dont use the system in place...

What distro you on?