I'm studying for Network+ certification (CompTIA) and am confused about subnetting. I know how to calculate subnets, broadcasts, IDs, subnet masks; but in actual practice how would this be done? For example, what equipment is needed.

Say I have a small company, a real-estate business, and they operate on a Class C internal network. They have a DSL internet connection. However, the Human Resources department shouldn't be able to access the Accounting Office's data through their subnet. Other than file permissions and all that, this question is about the networking side of it. So, my question is, how do we actually do a subnet?

Example:
Router address = 192.168.1.1
Subnet Mask = 255.255.255.128 ? (For 2 subnets)

1. Do I have to have 2 other routers for each subnet?

2. Do I have to have 2 switches connected to those routers? (1/per router)

And furthermore, do ALL devices receive the .128 subnet mask?

I've YouTubed and all the videos only talk about how to calculate subnets, not how to actually set one up which surprises me; or I'm just bad at searching YouTube.

Please help! Thanks in advance!

-Molly

Subnet is only a way to be within or outside of a number range. They don't secure the physical lan. If for example your two computer connect via the IP address and associated subnet then OK, they should do that all day long. If you want to access addresses outside of subnet then you need to route it out and tell it how to get out.

The combination of subnet and ip is separate from gateway/router. Many separate subnets could all contact a single server/gateway/router.



Subnets don't really secure a lan.

Almost no one would use a standard subnet either. Most folks would consider a classless based subnet.

Youtube isn't the place to go for a subnet calculator. It may have a web video on how to calculate it. Not sure anyone wants to do a manual calculation for than once.

Put your data into this calculator if you really need to make a classless subnet. http://www.subnet-calculator.com/