IP/Subnetting question

tel_s1234

Quick question for anyone who's set up networks professionally, do you stick to the guidelines when assigning IP's i.e only use ip's from 192.168.0.x range or 10.x.x.x range. I would have thought as long as your behind a NAT device when connecting to the internet, you could use whatever you wanted ?

Thanks

keenon

you would use private ip space inside the network, unless there is something that is truely needed to be out on the public network at any rate which would require a firewall or security at any rate.

this address range is more or less up to you but there are limitations and issues in a since when trying to decide A,B or C..

most places use a subnetted A space as it allows for great growth but at the same time if poorly designed a huge "cluster" in the making also a huge broadcast domain if you use the default mask

same deal with B

some smaller companies go for C as they don't ever expect growing pass 255 hosts

its all subjective to what your needing to do and what you may grown into. I currently use a 10 space with a /28 at home

Darthn3ss

tel_s1234 wrote:

I would have thought as long as your behind a NAT device when connecting to the internet, you could use whatever you wanted ?

Thanks

you could probably do that technically.. but say you decided to not use a private ip for some reason.. and you used something like 200.20.20.0/24 for your network address. when X host sends a request (Say HTTP) to a server at like 200.20.20.235, wouldn't your router try and foreward that out to the internet?

i don't know much about NAT yet.. forgive me if thats a retarded idea.

Paul Boz

You don't want to use public addressing on your LAN for many reasons. 1.) Those addresses belong to someone else. 2.) Private address spaces are well known as defined in RFC 1918 and make a LAN much easier to address and plan. 3.) From a design perspective there's no reason to use public addressing on the LAN because there are so many addresses allocated to private addressing that it's not necessary.

If you needed more addressing than allocated by the private address ranges (which is highly unlikely if not impossible) you could just use IPv6...

tel_s1234

So basically I can use these ranges of IP addresses

10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255

With any subnet class I choose i.e 10.10.x.x/16 ?

Darthn3ss

tel_s1234 wrote:

So basically I can use these ranges of IP addresses

10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255

With any subnet class I choose i.e 10.10.x.x/16 ?

excactly. you could use any sub netmaks with any of them (limits obviously - i doubt you could use a /8 on a class C or a /32 period.. :-p)