ran into something funny today and am still scratching my head on why this happened. I was trying to increase the number of ip addresses available from my dhcp server by changing the netmask from /24 to /20.
This was the first scenario, I changed the router's subnet mask to /20 to match that of my dhcp server. However, I did not change the subnet mask of any of the workstations with static ips and they stayed at /24. I connected a few workstations and wireless devices to the network and all of them got served the correct range, with /20 and are able to access the network.
My question to this first scenario is: Aren't all devices supposed to have the same subnet mask in order to work? Why are the workstations with static ip addresses and a netmask of /24 still working?
Then I tried the second scenario. This time the router's subnet mask remained at /24 and I only modified the DHCP server's subnet mask to /20. The outcome? The devices with static IPs with subnet mask /24 work. The devices served dynamic IPs with subnet mask /20 cannot access the network. My question to this is: If the previous scenario works with both subnets. Why is it in this situation it doesn't?
I'm not sure whether this is worth mentioning but the DHCP server is running ubuntu dhcp server.