Resubnetting

[Guest]

Hey all, I have resently realised I am getting low on ip addresses and have
read a few documents on resubnetting.

I currently have a simple 192.168.0.1 - 192.168.0.255 with a 255.255.255.0
subnet.

I thought if I simply change the subnet to 255.255.252.0 that would give me

192.168.0.1 - 192.168.0.255
192.168.1.1 - 192.168.1.255
192.168.2.1 - 192.168.2.255
192.168.3.1 - 192.168.3.255

Then all I would need to do is create a few more DHCP ranges, but I tested
this and anyone in the 192.168.0.x address space can't talk to people in the
192.168.1.x etc etc this makes sence to me but when I read KB 255999 and
other docs this should work, can some one clarify this for me?

Thanks in advance

 

[Kurt]

You'll need to change the subnet masks on ALL devices. If youe DHCP lease
time is long, any computers that are at less than 50%of their lease time
will need to be released/renewed.

....kurt

 

[Guest]

I changed them all to the new subnet and did a release and renew on the
addresses.

are you saying that what I said is correct? how many addresses should a
255.255.252.0 subnet give me?

I don't need a router to route between them?

 

[Neteng]

A 255.255.252.0 subnet will give you 1022 addresses for that one subnet.
Network ID 192.168.0.0
Host Range 192.168.0.1 to 192.168.3.254
Broadcast 192.168.3.255
This is one subnet. What your doing is supernetting, which is kinda the
reverse of subnetting. You're combining multiple networks instead of
splitting up one big network into smaller ones. Best practices is to leave
your subnets at /24 unless there really is a need to make them bigger. If
you need more space, create another /24 network and put a router in between.

 

[Guest]

so if I create a dhcp scope for 192.168.0.1 to 192.168.3.254 with a
255.255.255.0 and an exclusion range for my servers of 192.168.0.1 -
192.168.0.50 all clients that pick up addresses in the 192.168.0.51 -
192.168.3.254 will beable to communicate with each other and the servers?

Thanks in advance for you help

 

[Neteng]

Your subnet mask should be 255.255.252.0 not 255.255.255.0. All clients
should be able to communicate then.