[CentOS] Subnet expansion

Thu Jul 28 10:47:10 UTC 2011
Fajar Priyanto <fajarpri at arinet.org>

On Tue, Jul 26, 2011 at 7:53 PM, John Hodrien <J.H.Hodrien at leeds.ac.uk> wrote:
>> Currently I have this network:
>> 10.1.16.0/22.
>> 10.1.16.0-10.16.17.254 are DHCP managed
>> 10.1.18.0-10.1.19.254 are statically assigned
>>
>> If I need to expand it to:
>> 10.1.16.0/20
>>
> I think the answer to this part is not trivially.  A machine in the /20 subnet
> will expect to be able to talk directly to a machine within the /22, but that
> machine will want to talk via a router.  You can hide subnets within subnets
> using arp-proxying, but I'm not sure there's an easier way.
>
> A machine within the /22 would be able to talk to any other machine within
> that /22 (even if they're configured to use /20), but won't be able to happily
> talk to machines within the /20 but outside of the /22.

Hi John,
Thanks for helping. I have some discussion also with friends in the
physical world, and they suggest:
1. Keep the current network 10.1.16.0/22
2. Create another network 10.1.20.0/22 (half static, half dhcp)
3. Setup a router so that the two network can talk to each other.
4. This will offer no disruption to the current network setup at all.

One issue that I see may be coming is that, since I want to allocate
10.1.20.0/22 to a specific VM that belong to a specific team,
I may have to setup the DHCP based on MAC. Could be very tedious.