Extending IP addresses

[Gunner 1]

Hello,
We have, within our company extend our range of IP addresses as it becomes full. Consider a network 194.30.30.0 / 16 is 255 addresses which are no longer sufficient today. Can we keep the same IP address by changing our model of the standard network CIDR, i.e that we no longer consider the class of address (A, B, C), through such a mask 255.255.0.0 ? How to operate on my two domain controllers to manage this migration to better knowing that LIP is hard on each position? In fact, the ideal would be to keep the IP Address and essentially change the mask on each network device and positions. Thank you, guide me because this migration must act quickly.

[Snake08]

Hi,

Consider a network 194.30.30.0 / 16 is 255 addresses which are no longer sufficient today.

I suppose it's rather 194.30.30.0 / 24

Can we keep the same IP address by changing our model of the standard network CIDR, ie that we no longer consider the class of address (A, B, C), through such a mask 255.255.0.0 ?

It's very dirty but in absolute terms, yes you could. This means that you have a single flat network 194.30.0.0 ==> 194.30.255.255. However, some equipment and software may react badly because you put a class C (194.30.30) with a mask of class B. Moreover, as all addresses 194.30.0.0 ==> 194.30.255.255 is supposed to be locally (from your netmask), you can no longer go on the official websites that have addresses that you are spirited to "steal ". So essentially, this is not good. Either you ask for another class C to your provider (it will be hard but why not). Either you use the private address (10.0.0.0, a class A all to yourself) and you keep your public addresses (194.30.30.x) for machines that can not / should not change your address and the translation address 10.0.0.0 to 194.30.30.x.

Thank you, guide me because this migration must act quickly.

A migration plan address is never done "as quickly as possible." You should at first to try to anticipate the side effects.

[Gunner 1]

Hello,
Thank you for your response. In fact we have a fixed address provided by our ISP with a mask of 255.255.255.255.
So if I understood it better than I resetting all my IP with a private address ranges (eg 192.168.0.0/16 seen that the 3rd class is apparently from 192.168.0.0 to 192.168.255.255 is 65,535 addresses)?
What is the best approach in terms of the order of migration, change begins with the domain controllers or do it gradually?

[Snake08]

Hi

So if I understood it better than I resetting all my IP with a private address ranges (eg 192.168.0.0/16 seen that the 3rd class is apparently from 192.168.0.0 to 192.168.255.255 is 65,535 addresses)?

It seems to me dangerous to use a class C with a mask of class B. Intellectually, it is disturbing and I do not know if all equipment / software support it. I suggest you rather use a class A (10.0.0.0 / 8) or class B (172.16.0.0/16). They are planned for this.

[Big Fish]

Hello

What is the best approach in terms of the order of migration, change begins with the domain controllers or do it gradually?

First define your new addressing plan with a fine network pattern and an Excel spreadsheet with each machine and each machine interface of the old address and new address. Then I will use the ability of almost all the machines have 2 IP on same interface. You put on all your machines / servers / routers 194.50.50.x an address and an address 172.16.xx
This way your machines continue to function whatever the address used (in the beginning, they will respond with 2 IP addresses). Attention to migration addressing plan, this does not affect the IP configuration of machines, it also concerns the configuration of some applications (DNS, mail, business application that connects to a database,). Then gradually you finish your migration by removing the address 194.30.30.x all your machines.

[Gunner 1]

Hi
Really thank you for the clarification.

This way your machines continue to function whatever the address used (in the beginning, they will respond with 2 IP addresses).

Regarding the ability to maximally 2 IP address on the same interface, I confirm you that it happens at the level of advanced settings parameter range IP. am I right? If wrong please guide me to the correct concept.