Local Network IPs - 10.0.0.0/8 or 192.168.0.0/16?

mike9010 asks: "After reading a few articles on the net about networking, I have come up with a question. It seems that most of them say to use 192.168.0.0/16 for a local network. Why not use 10.0.0.0/8 though? It is my understanding that it can hold a lot more IP addresses, and it is also prettier." What local network range are you using for your networks?

Comments

IP Subnetworking

[hawkstone]

From the IP subnetworking HOWTO:

There are also special addresses that are reserved for 'unconnected' networks - that is networks that use IP but are not connected to the Internet, These addresses are:-

* One A Class Network
10.0.0.0
* 16 B Class Networks
172.16.0.0 - 172.31.0.0
* 256 C Class Networks 192.168.0.0 - 192.168.255.0

The one most often used by home networking products is 192.168.1.x in my experience, not the full /16. They are designed to hold 254 addresses, no more. Why are these designed for only a small number of IP addresses? Well, the home routers often have 4 ports, with maybe wireless. Are you really going to have a few hundred clients? Anyway, it's probably best to stick with the 192.168.1.x for a small network if you're planning on connecting to one of these. If, not, do whatever floats your boat!

Re:Hi, I'm ignorant. Pleeztameecha!

[Medieval_Gnome]

It is a method of indicating how many bits in the address are part of the 'network' number, as opposed to the 'host' number. For example..

In 10.0.0.0/8 that means there are 8 bits that identify the network (10.x.x.x) and 24 bits (IP addresses are 32 bits, 8 bits are already used for network; 32-8=24) for the machine number (the x.15.53.45)

So now, for '192.168.0.0/16'. The 192.168 part is the network part, and the '/16' means the last 16 bits are used for hosts. When the slash-number is larger, that means the person with that IP range has less IPs. /24 means the user has 254 hosts at their disposal, while a /8 means over 16 million.

I really hope this helps, sorry I'm not the greatest at explaining things.

CIDR!

[tachyonflow]

Welcome to the world of classless routing!

192.168.0.0/16 certainly does exist. The first three bits has not dictated the netmask for years. See RFC1817 for more information on this. Here's a relevant excerpt (emphasis added):

Classless Inter-Domain Routing (CIDR) ([RFC1518], [RFC1519]) is deployed in the Internet as the primary mechanism to improve scaling property of the Internet routing system. Essential to CIDR is the generalization of the concept of variable length subnet masks (VLSM) and the elimination of classes of network numbers (A, B, and C). The interior (intra-domain) routing protocols that support CIDR are OSPF, RIP II, Integrated IS-IS, and E-IGRP. The exterior (inter-domain) routing protocol that supports CIDR is BGP-4. Protocols like RIP, BGP-3, EGP, and IGRP do not support CIDR.

Re:FP...

[afidel]

These are not BS. This was an IP block set aside for future use and Apple, MS, Sun, and others decided to use it for local link zero config stuff. This was codified by the ietf and is specified in RFC 3330 and other places.