I have a small domain that supports approx 100 users in 7 buildings. We are running a Citrix virtual environment, I run on a private network address of 192.168.100.xxx SM 255.255.255.0 I am out of IP addresses and would like to increase by changing the mask to 255.255.254 that should give me plenty of room for growth. My GW is 192.168.100.254. I would like to use IP addresses 192.168.100.xxx and 192.168.101.xxx. Can I modify current scope or just create a new one and is there anything to watch for? We have a 24/7 operation in fire and rescue so downtime needs to be minimal. We do have a firewall Cisco 5510 that we set behind. Thanks in advance for advice.