On the last Saturday, I and my friend are trying to connect two computers directly using a USB cable and start communication between these two computers without the help of any external DHCP server. As I mentioned in my previous post we cannot use an ordinary USB cable to connect two computers directly. It may burn the USB port.
[ To know more about it please follow the link below.
http://www.corenetworkz.com/2009/10/can-i-connect-two-computers-using-usb.html ]
In this project, we avoid using the router or any other DHCP servers. As we are not using the Ethernet adapters we cannot set any static IP address. So without the presence of external DHCP server and static IP address our both computers will get APIPA from Windows Operating System.
[ To know more about APIPA please click on the link below.
http://www.corenetworkz.com/2008/02/how-to-resolve-issue-when-ip-getting-is.html ]
So the IP address our computers got was a 169.254.X.X range. Fortunately, the IP address gained by our computers were in the range 169.254.1.X and it started to communicate with each other.
It is sure that APIPA computers can communicate with each other as their subnet mask is 255.255.0.0 (Class B address). So as the subnet rules say the network address of APIPA is 169.254.0.1 and the broadcast address is 169.254.255.255. Any address comes in between this range can communicate with each other. Because it is a private IP address we cannot use APIPA to get the Internet connection to our computers. For Local networks and Intranet APIPA is enough.
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[ To know more about it please follow the link below.
http://www.corenetworkz.com/2009/10/can-i-connect-two-computers-using-usb.html ]
In this project, we avoid using the router or any other DHCP servers. As we are not using the Ethernet adapters we cannot set any static IP address. So without the presence of external DHCP server and static IP address our both computers will get APIPA from Windows Operating System.
[ To know more about APIPA please click on the link below.
http://www.corenetworkz.com/2008/02/how-to-resolve-issue-when-ip-getting-is.html ]
So the IP address our computers got was a 169.254.X.X range. Fortunately, the IP address gained by our computers were in the range 169.254.1.X and it started to communicate with each other.
It is sure that APIPA computers can communicate with each other as their subnet mask is 255.255.0.0 (Class B address). So as the subnet rules say the network address of APIPA is 169.254.0.1 and the broadcast address is 169.254.255.255. Any address comes in between this range can communicate with each other. Because it is a private IP address we cannot use APIPA to get the Internet connection to our computers. For Local networks and Intranet APIPA is enough.
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10 Comments
The correct Network ID is 169.254.0.0 and the Broadcast ID is 169.254.255.255 the assignable addresses for this class B network are 169.254.0.1 to 169.254.255.254.
ReplyDeleteThank you Exipheas,
ReplyDeleteYou are absolutely right. The network id of APIPA is 169.254.0.0
While writing the network id on my post ,actually what was in my mind is the first valid IP address in APIPA. The first IP address is 169.254.0.1
I understand my second mistake (broadcast address). I don't know why did I made such an error while typing the post. I will edit that error soon. Once again my thanks to pin point the mistakes I made.
Do you know if there is a way to determine the IP's of all connected stations?
ReplyDeleteLet's say I have 5 computers in a LAN and they assign themselves an IP by APIPA.
Now I can only access one machine (because the others are embedded systems), how can I find out the other IP addresses?
Thanks,
Alex
@ Alex
ReplyDeleteAPIPA is assigned by the OS it self and there is no external DHCP server works for it. So I don't think there is any way to find the APIPA ip address of other computers in the LAN without checking each system manually.
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guys can you help, my hp pavillion cannot change the Ip 169.254.x.x i have already ipconfig/release=ok renew=error im using win7 the laptop can communicate trough other computer in the network that has an ip of 192.168.x.x my other pc can access the net. but the laptop cannot access internet help plz im troubleshooting this for 3 days and i have no luck...
ReplyDeleteI recommend you to assign a static IP address in hp pavillion in 192.168.X.X range and check for the issue. To know more about this issue follow the link below.
ReplyDeleteHow to Resolve APIPA
Hi,the post is really good and informative.I have one doubt suppose there are five machines connected to a switch and 3 of them are getting ip address from DHCP server and 2 of them are getting the APIPA.So my question is will the 2 APIPA machines communicate with the other 3 machines? and will the 2 APIPA machines communicate each other please reply.
ReplyDelete1. Your APIPA machines cannot communicate with other 3 devices getting IP addresses from external DHCP server since they are in different network address.
ReplyDelete2. APIPA machines connected in the same network can communicate each other