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APIPA, also known as Automatic Private IP Addressing, is a feature used in Windows operating systems. It comes into action only when DHCP (Dynamic Host Configuration Protocol) servers are available. When the DHCP client first comes on, it will try to establish a connection with the DHCP server in order to get an IP address. It is when this server is (or at a later point becomes) unavailable, that APIPA will kick in.
As the client is unable to connect with the server, APIPA will automatically try to configure itself with an IP address from an specially reserved range. (This reserved IP address range goes from 169.254.0.0 to 169.254.255.255).
After an IP address is obtained using APIPA, the client will then verify that their IP address is a unique one on the LAN. This is done utilizing ARP. According to Microsoft guidelines, APIPA will also check regularly to see whether the DHCP servers are available. If at any point it does become available, then the APIPA service will discontinue itself de-allocating the IP address it has obtained, and allow the DHCP server to allocate a dynamic IP address.
When APIPA takes over and your client has been assigned an IP address, the client will be able to communicate with other computers also on that LAN which have also been configured by APIPA, or failing that, which have been assigned a static IP address in the range mentioned earlier (so and IP address like 169.254.x.x, where ".x.x" are the identifiers unique to that particular computer).
However, if you are connected to the internet without a NAT, or even a proxy server, or you use routers, you might want to turn the APIPA feature off. For more information on this you can go to straight to the source at Microsoft's Help and Support pages on "How to use automatic TCP/IP addressing without a DHCP server" at this address http://support.microsoft.com/kb/q220874/
All the information you need to on how to turn APIPA off, is contained here.
In essence the APIPA service is a fail-safe device put in place by Microsoft to make sure that everything runs smoothly. There is nothing that you need to do about it as it all happens in the background, and at speeds and times of which you are unaware of. In fact, by the time you detect that your DHCP server is unavailable, and you try to rectify the matter, APIPA would have already taken the proper steps necessary to keep your client running smoothly.
What else can I help you with?
Why was apipa created?
Automatic Private IP Address was basically made so that clients which could not get an IP address automatically from a DHCP server could configure its own Private IP address until it can obtain address from the DHCP server which will override the APIPA and become the new IP address.
What is a apipa address?
An APIPA stands for, Automatic Private IP Address. Basically the majority of people use DHCP to obtain there IP address and configurations. For this to work, a DHCP server must be running. DHCP servers are found in home routers, gateways, modems, or corporate servers. However, If there is no DHCP server that is reachable, you will get an APIPA. APIPA is a range of IP address just for Microsoft operating systems. An APIPA ranges from 169.254.0.1 through 169.254.255.254. When it is activated, it constantly looks for a DHCP server to get a configuration from. When it finds a proper configuration, APIPA is disabled.
What are some benefits or uses of APIPA?
One benefit of APIPA is that it allows you to personalize and configure your IP address. It also is completely free.
How do you find an APIPA address at first glance?
APIPA - Automatic Private IP Addressing uses a range of addresses 169.254.0.0-169.254.255.255 with a subnet mask of 255.255.0.0. If your address starts with 169.254, there is a good chance you are using APIPA.
Computer A has an IP address of 169.254.45.21 what does this mean?
This is an APIPA (Automatic Private IP Addressing) address. When Windows computers can't get an IP address from a DHCP server, they automatically assign themselves this address.
What is apipa process?
APIPA (Automatic Private IP Addressing) is a feature in Windows operating systems that allows devices to automatically assign themselves a private IP address in the absence of a DHCP server. When a device with APIPA enabled cannot find a DHCP server to assign it an IP address, it will assign itself an IP address in the range of 169.254.0.1 to 169.254.255.254. This ensures that the device can still communicate on the local network, even without a DHCP server.
What is an example of APIPA?
An example of APIPA (Automatic Private IP Addressing) is when a device is unable to obtain an IP address from a DHCP server, so it assigns itself a link-local IP address in the range of 169.254.0.1 to 169.254.255.254 to allow for local network communication. This temporary address helps devices communicate within the same network segment until a proper IP address can be assigned.
What does 169.254.10.1 indicates?
169.254.10.1 is an IP address generated automatically by a computer when it is unable to lease an address from a DHCP server. It is called an Automatic Private IP Addressing (APIPA) address.
What is APIPA and How would you recognize it?
Automatic Private Internet Protocol Addressing (APIPA) is a common alternative to the use of the Dynamic Host Configuration Protocol (DHCP) to request and retrieve an Internet Protocol (IP) address for a host. APIPA simplifies the assignment of IP address and subnet-mask configuration information to hosts in small networks. When APIPA is used, the operating system allows the assignment of a unique IP address to each station on a small local area network (LAN). This avoids the administrative overhead of running a DHCP server or manually setting IP configuration information.
If no dhcp server is available on a network what type of configuration must computers on the network use for assignments of IP addresses?
Usually the systems will be assigned an APIPA address in the range 169.254.x.y in order to use resources in their own LAN. The APIPA configuration can also default to static IP addresses if necessary. If APIPA is not being used then the only way to use the network is to manually assign a static IP address and all of the required settings.
When a computer gives itself an auotmatic private ip address apipa it also includes a valid default gateway address?
When a computer assigns itself an Automatic Private IP Addressing (APIPA) address, it typically does not include a valid default gateway address. APIPA is used when a device fails to obtain an IP address from a DHCP server, allowing it to communicate with other devices on the same local network segment. The assigned IP address falls within the range of 169.254.0.1 to 169.254.255.254, but without a default gateway, the device cannot access external networks, such as the internet.
What does it mean when a computer has an APIPA address on its network interface?
APIPA stands for Automatic Private IP Address Generally it will be in the range 169.254.0.1 up to 169.254.255.254 (subnet of 255.255.0.0) This is the IP address a computer gets when it is set up pick up an IP address automatically and there is no DHCP server... or the computer can't see a router. The computer will be able to connect to any other computer on the network with an IP in the same range, but will NOT be able to connect to the internet.
