Running a network behind a ZyWall USG 200. Our subnet has around 100-110 devices connected at any particular time. Recently some users were having trouble with getting a DHCP address (keep getting self-assigned IPs) and upon investigation I noticed that there were 150-200 addresses assigned in the DHCP table on the router. I looked into the table and it is showing one or two devices with 30-50 IPs assigned:
I think that this is filling up the available address range and preventing other devices from leasing an IP. Interestingly, as I refresh the table this number fluctuates and different devices are hogging the addresses.
Why would this be happening? How can I prevent this so that all devices can pull an IP and connect to the internet?