IP and LAN question?

Question

Hi guys

I sometimes see a LAN IP on the form of x.x.x.x/y

, for example 194.165.155.17/30, now I'm wondering what could this number after the slash be? is it the range of IPs in the LAN?

thanks in advance

Answer 1

The /30 is the subnet indicator for the the rest of the IP address.

All IP's have an IP and a Subnet mask.. the /30 would indicate a subnet mask of 255.255.255.252  which allows 2 hosts. The subnet ID would be 194.165.155.16 (in your example) with a "broadcast address" of 194.165.155.19 allowing 194.165.155.17 and 194.165.155.18 as usable IP's for the network.

If you want to see how that works go to http://www.subnet-calculator.com enter the IP and under the "Mask Bits" enter 30. It just a short hand for the subnet mask.

If you want to learn subnetting visit http://www.learntosubnet.com

Hope that helps.

Answer 2

It's the number of bits in the address (starting at the right) that comprise the range.