Private and Public IP Addresses Explained

Public IP Addresses

What is Public IP address

Public IP Addresses (also known as Static IP Addresses) are IP addresses that are visible to the public.Because these ip addresses are public, they allow other people to know about and access your computer, like a Web server.In some cases, you do not want people to access your computer or you want to restrict certain individuals from accessing your computer or server.

Private IP Addresses

What is Private IP address

These addresses can be used on a private network, but theyโ€™re not routable through the public Internet. This not only creates a measure of much-needed security, but it also conveniently saves valuable IP address space.

Current Private IP addresses as follows

Class A

10.0.0.0 through 10.255.255.255

Class B

172.16.0.0 through 172.31.255.255

Class C

192.168.0.0 through 192.168.255.255

51 thoughts on “Private and Public IP Addresses Explained

  1. This is perhaps not a really vital distinction but a Public IP Address is NOT automatically a Static IP Address.

    On my home DSL connection, for example, I have a Dynamic IP Address – it is assigned by my ISP and will sometimes change (hence Dynamic) but it is the IP address visible to the world (Public) for all computers on my network.

    Within my network, of course, Class C addresses are used and information is routed to the appropriate machine using those addresses by my router.

    I would say that the Public IP Address is the one broadcast or transmitted with request packets so that information may be routed accurately to your access point, router, or stand-alone computer/workstation; or broadcast so that your access point, router, or stand-alone computer/workstation may be located by other machines/services on the public network or internet.

  2. Public IP address can be static or dynamic, depending on what you have applied with your ISP.

    Most of the case a static public IP is used if the purpose is to have a fixed IP address (Web Server, FTP Server and etc.).

    The private IP address above is true and for standard use your private network must follow these IP addressing.

    **************************************
    Class A
    10.0.0.0 through 10.255.255.255

    Class B
    172.16.0.0 through 172.31.255.255

    Class C
    192.168.0.0 through 192.168.255.255
    ***************************************

    All IP address except the above mentioned is for public use (From Class A to Class E).

  3. Public ip address are unique n used by web servers like yahoo.com , google.com
    they r paid ip address
    Private ip address r unique within a LAN
    they r used for general purpose n are free

    The valid private ip address are
    Class A 10.0.0.1 to 10.255.255.254

    Class B 172.16.0.1 to 172.31.255.254

    Class C 192.168.0.1 to 192.168.255.254

    Rest are public

  4. Actually my question is. i wanna logon to other computer remotely i have all that computer details
    for example= lan ip and public ip. pls write me in details

    best regards

    Munir

  5. Sir, With reference to Charles M.Kozierok’s TCP/IP guide i concluded that private ip address is correct as given above. Please give one correct info as these are sensitive details(in my point of view).

  6. In my opinion I think most of you have skipped over a very important detail. Private IP addresses are not Internet route-able and therefore cannot be used as public addresses. This is why home and business type routers all support what is called NAT, network address translation. The outside interface (public facing) generally has a Public IP given to you by your ISP (Internet Service Provider). This IP address is not required to be public and can be private but there has to be NAT somewhere before actual Internet access is established.

  7. hai sir,
    i want to connect my computer(office) in a lan network from my home through internet with using any softwares, can u help me???

  8. hi dude,
    can i use public ip inside LAN? example i have 10 host connected to switch. i am using DHCP server in my LAN scope of the DHCP server is 11.0.0.2 11.0.0.254, subnet mask: 255.255.255.0 dns:4.2.2.2. default gateway would be 11.0.0.1. i am using router and enabled NAT.. i know i can access google since i am using NAT…

  9. Please,what is the effect of having two pc’s in a network with different default gateways and different DNS server addresses?.

  10. i have public ip for third party.how can i log on in that pc? pls explain me.
    Actually my question is. i wanna logon to other computer remotely i have all that computer details
    for example= lan ip and public ip. pls write me in details

  11. An example of a public IP address is 192.168.0.2 considering your modem/router has an IP address of 192.168.0.1.

  12. Hi, Is it legally to use IP addresses 192.168.x.x within ur laptop to configure and practice for learning purposes. Please confirm. Cheers.

  13. A public IP address can be static or dynamic. A static public IP address does not change and is used primarily for hosting webpages i mean (more clearly)by web servers while a dynamic public IP address is chosen from a pool of available addresses and changes each time one connects to the Internet..!!! Most people have a dynamic public IP address..ISP assign the public ip address to the computers connected to the dsl modem.
    public ip address are unique while private ip address are not..!!!
    thanks..!! have a nice day..:)

  14. helo guyz,i’m still new in this networking infact jst undergoing my training,so my question, if i have an ISP supplying me internet service and they have DHCP activated which of d ip is public, is it d ISP IP.

  15. A public IP address can be static or dynamic. A static public IP address does not change and is used primarily for hosting webpages i mean (more clearly)by web servers while a dynamic public IP address is chosen from a pool of available addresses and changes each time one connects to the Internet..!!! Most people have a dynamic public IP address..ISP assign the public ip address to the computers connected to the dsl modem.
    public ip address are unique while private ip address are not..!!!
    thanks..!! have a nice day..:)

  16. hi sir, gud eve! I want to know that how did this ip addressing classes configured like class A, B, C………..etc

  17. I will answer some questions hopefully they will help previous visitors andnew visitors.
    @Parinitia

    Before VLSM/CIDR and classlful subnetting, every company was given a block of addresses to use. For example some companies would be given class A because they needed alot of addresses, another would be given class B because they needed more network and slightly less address. They broke the addressing scheme down into sections so that they could provide the requirements for businesses. Even though they had broken it down into lists so it provides compatibility, businesses were still given too many addresses that they did not need.

    Now the problem, companies were getting 100s of addresses and slowly they realised that they are running out and that is where NAT and subnetting came into place.

    Class A

    10.0.0.0 through 10.255.255.255

    Class B

    172.16.0.0 through 172.31.255.255

    Class C

    192.168.0.0 through 192.168.255.255

    You will never, ever see any of those IP addresses on the Internet. They are private addresses that businesses can use to create a network and break it down. Public addresses are ones that are given by yout ISP: they look something like this:

    74.125.224.72
    8.8.8.8

    So, they realised that they were running out of addresses and they introduced CIDR in 1993. CIDR is basically, you are giving one ip address or block, and you break that ip address down so you can use it with multiple devices. This with the aid of NAT changed things.

    In the future, we will not need to worry to much about address issues because IPV6 is already out and that has many, many addresses.

    @nik’s computer

    These addresses are given by your ISP, you get the address from a DHCP server and you needed a connection to their servers, i.e. a leased line or a shared line.

    @yusuf

    Every computer at home or business envrionment will have two addresses. Internal and external. Internal addresses are private addresses commonly seen as 192.168 and 172.16. Public addresses are IP like 88.10.25.11 and so on. The public ISP is the answer.

    @Bala, yes it is legal, you have to have IP address for communication.

  18. if u want to create a web server u need public ip. bcoz only public ip are accessible from remote pc. private ip are not accessible directly from client pc.

  19. Hey guys.. Is it true that having public IP address transiting in closed network like transmission network is less critical than it could be if it was in pure IP network..huh?

  20. if u say so that each time i connect to internet my ip address changes, then how could they find out the one who do cyber crime? if they have record of that ip then there database could be so much vast!!

  21. example for public ip 193.124.241.147 (public ip’s are unique and no copy of that same ip will be available else where) there is a small note:
    being unique in the sense is when you(host) are connected to the internet only.
    for example microsoft has it own public ip 193.124.241.147. you can use the same ip as your ip with-in local area network until you are connected to the internet, if you are connected to the internet there will be two possible ip’s with the same name on the internet,so when a person with his network tries to access the microsoft page on internet the virtual routers on net may be confused where to send the clients request.that is why a public ip address should be unique.

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