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

Posted by Cliff on from the matters-of-personal-opinion dept.

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?

9 of 215 comments (clear)

  1. What about 172.16.0.0/12? by Sunlighter · · Score: 5, Insightful

    This is an intermediate one that isnt widely used.

    I dont think it matters too much; few businesses have as many as 64,000 computers, so the 192.168 is big enough. But the 10 makes it easy to do interesting things with the other numbers, like making the first number the department number, etc.

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    1. Re:What about 172.16.0.0/12? by Magic+Thread · · Score: 5, Interesting

      I use 172.16.0.0/12. That way I don't have any problems connecting over VPN to networks that use 10.0.0.0/16 or 192.168.0.0/8.

  2. I use by The+Clockwork+Troll · · Score: 5, Funny
    I use the 66.35.192.0/18 block.

    It doesn't seem to conflict with anything important.

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  3. Why? Why not? Because. by MattCohn.com · · Score: 5, Interesting

    There is no real reason to use one or the other except that many devices come with built in static IP addresses. I've seen some with 10.x addresses, others with 192.168.x addresses. I guess not looking at that, it just comes down to choice. I like 192.168 and use it on my home network... but my work network uses 10. JUST GO FOR IT MAN!

  4. IP Subnetworking by hawkstone · · Score: 5, Informative
    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!
  5. Re:Hi, I'm ignorant. Pleeztameecha! by Medieval_Gnome · · Score: 5, Informative

    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.

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  6. CIDR! by tachyonflow · · Score: 5, Informative
    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.
  7. There can only be one! by Anonymous Coward · · Score: 5, Funny
    I use a /24 chunk of 172.16.0.0/12, because it's a chunk that is easy for me to remember -- it maps to my birth date.

    On the 17th day of February, in the year of our Lord 1600, I was born a highlander. I am Colin McLeod of Clan McLeod and I cannot die.

  8. Re:FP... by afidel · · Score: 5, Informative

    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.

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