Ady Wicaksono Daily Activities

Private IP Address

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Current Internet Protocol widely use is IP version 4. This IPv4 in short term, allocate 32 bit address, so there’re maximum 2^32 = 4.294.967.296 IP addresses in the Internet. Big number but seems will not enough šŸ™‚

IPv6 has bigger address space, 128 bit, so we will have 2^128 = 340.282.366.920.938.463.463.374.607.431.768.211.456 IP addresses in the internet, very big number :D.

However, IPv6 is not widely deployed now, some solution already proposed to minimize the address space limitation problem on IPv4, one of them is IP private. RFC 1918 defines IP private which should not used on public internet:        -  (10/8 prefix)      -  (172.16/12 prefix)     - (192.168/16 prefix)

Normally we will use this address on our home or office and we will able to access internet either using proxy or NAT/IP Masquerade solution.

Written by adywicaksono

November 7, 2007 at 4:25 pm

Posted in networking

One Response

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  1. The main idea of the IPv6 was to forget about NAT and give the ability for each device in the Net (PCs, mobile phones, tosters, etc) have their own IP. This IP will be reachable from anywhere, because it’s “real” IP. Another idea was to reduce routing tables on core routers. It will be similar to phone numbering scheme – prefix defines the geographic position of the host. Currently 2 PC in the same room may have absolutely different IP addresses (if they got them from different ISPs) and this is really ugly šŸ™‚
    2 years ago I wrote master degree work about transition to IPv6 mechanisms (it’s in ukrainian). But after some analysing I found that there are a lot of unused (reserved in terms of IANA) IP addresses blocks. Just have a look on IPv4 address space. How could it be that a lot of engg “cries” about absence of IP addresses, when almost 30% of whole address space isn’t used? šŸ™‚
    Probably that’s the answer on question why we still use Private IP Address.


    November 16, 2007 at 10:18 am

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