Hi we are running out of IP's on our network and we want to change the subnet mask to increase the available IP's on our network. We are currently running a mask of /23 and want to move to a /21. We have a flat network with no routers and using DHCP. I will like to know if by changing the mask on our network will cause any issues with AD 2003 and Exchange 2003? We are not running a exchange cluster.Thanks in advance for any assistance.

Hi Benaldo,Thank you for posting in windows server forums, When you plan to restructure IP for your org , you need to consider AD as a priority. I will answer with best of my knowledge.a) Your DC IPaddress would be changed and if you have installed and configured DNS server on the DC then your DNS server IPaddress would be same as DC Ipaddress.b) You will be clearing your old subnet /scope from DHCP server and will be assigning new Subnet / scope with new mask for which you will create new exclusion, new reservations along with the DNS server Ipaddress.Your clients ( mixed ) should be able to communicated to AD for authentication for which they should have appropriate DNS server configured and which you are planning to provide through DHCP which is valid. c) The only important part of Active directory is DNS from communication stand point , also after the changes please restart the netlogon service once to get the changes effectively. With respect to exchange i would suggest you post in exchange forum http://social.technet.microsoft.com/Forums/en-US/category/exchangeserversainath !analyze

Hello,with using one big subnet you have the disadvantage for a big broadcast domain, where all devices can directly talk to each other, this generates lot of network traffic.To prevent problems you should avoid this and better use VLANs with switches or routers to separate them, Layer3 devices will drop broadcast traffic.In the moment we also have a large broadcast domain, /20, and we are working on it to devide it with VLANs on our switches. Best regards Meinolf Weber Disclaimer: This posting is provided "AS IS" with no warranties, and confers no rights.

hi Benaldo,Did you had a chance to go through the suggestions ?sainath !analyze

Hey Guys,Thanks for the suggestions, it sounding good and i will look into it. After the restructuring takes place i will update you all if any issues occured.