Understanding IP Addresses

I'm looking for some help understanding IP addresses, subnet masks and default gateway. I'm not sure if this is the right forum as my question relates to PLC networking but it is on Ethernet so I think it is the same.

Can anyone actually explain what the IP address and subnet masks mean:

For example in the addreses below what does the 192 mean, what does the 255 mean, etc.

IP: 192.167.100.253
Subnet Mask: 255.255.255.0
Default Gateway: 192.167.110.1

I'm most confused about the function of the subnet mask and the default gateway.

 

In a nutshell the default gateway refers to your router usually.. your gateway in and out of your network.
IPs like 192.168.1.1 with subnet 255.255.255.0 is like nnn.nnn.nnn.hhh
n = network , h = host... so all computer with IPs like 192.168.1.x (where x is 2-254) are one the same network.. 192.168.2.1 with the same mask, is an entirely different network...

192.168.001.001
255.255.255.000
nnn.nnn.nnn.hhh
192.168.1 is the network there...

010.010.020.001
255.255.000.000
10.10 is the network ..
any easier?

So if 2 nodes (hosts) cannot ping each other it could be because they are not on the same network...


PS. this is a quick and dirty example.. try not to critique it without a full explantion...

 

So in the first example network 192.168.1 could have up to 999 different devices but the second network 10.10 could have 999 * 999 different devices?

How can two devices on different networks communicate? They go through the gateway?

 

I tried to keep it easy.. but in the networking world your 'top' number is 255.. more like 254. And another simple mantra is "Routers define Networks" so you'd need a router to connect the 192.168.1.x to 10.10.0.x network.. basically.
I say basically because we have not discussed routable and non routable protocols....

Yes, you've got the concept for network vs host addresses correct just replace 999 with 254...lets not get into subnetting or supernetting.. keep it simple.. because in the 10.10.x.x example you'd get a lot more hosts...65,000?

Need a calc.. http://www.wildpackets.com/products/free_utilities/ipsubnetcalc/overview

see there is a lot more to networking than 'My Network Places'...lol

 

I recently ran into a book, that talked about tcp/ip. 1000 pages to learn. Fun Fun!

So, in saying, truly learning Internet Protocol addressing is very fun!

 

not a shot at anyone

the best book i ever bought was tcp\ip for dummies (still use it for ref.)
it goes into detail about sub netting, super netting, dns, wins, dhcp, easy to read and understand.