Hello All,

A few days back I gave a small introductory training session to some freshers on networking, ip addresses, subnets, gateways and dns.

However after that one question comes to my mind about subnets.

Can we have multiple networks with adjacent subnets on a common LAN connection or do they need to be physically different too?

For example can we have 192.168.1-31/27 and 192.168.32-63/27 on the same LAN switch as independent subnet islands? Theoretically it looks so.

When we set up network information on a host pc, we give the IP address and subnet. However, how does that host know the starting and ending ip of its subnet so that it will not talk to its adjacent subnet? ......For example, how does host 192.168.1.33/27 know that its subnet starts from ip 32 upto 63 and will not talk to 31 or less?

Or do the subnets have to be on different LAN switches?

Any pointers to this will help.