Apipa address connection to remote site?
I am wondering... I have 1 AD domain with 2 sites. Each site has a dhcp server. In one site the dhcp fails. Computers in that site are assigned APIPA addresses. If I am in the other site (with the functional DHCP) and I assign a computer an static APIPA address, can I use RDP to connect to the other computers in the remote site.
When both sites have the dhcp service up, although they are on different subnets rdp functions with no problem.
Thank you.
Answers & Comments
Verified answer
* Short answer:
No. Not in your case.
* Detailed answer:
This scenario is basically about routing. If you assign a computer a static APIPA IP address, you'll also need to assign it a default gateway, which should be obviously in the 169.254.0.0 /16 network, for example, 169.254.0.1. However, do you have a router interface that's connected to that computer's physical network and that has such IP address (169.254.0.1) so that it can route APIPA packets to the other network? Probably not.
Also, do computers on the other network (failed DHCP) have a default gateway configured in the 169.254.0.0 /16 network? Probably not. You need a default gateway that you can reach so that you can communicate (RDP, ping, etc.) with another network.
Now imagine that you do have a router configured with APIPA addresses on two interfaces that are connected to each network... Wait! You can't do that! Routers are designed to connect different IP networks, so you can't configure two interfaces of the same router on the same network (APIPA).
Finally, APIPA is not supposed to be used with routing, as its main purpose is to easily allow communication among computers within a local network.
. . . Note: You should know that there are some scenarios in which APIPA can be used with routing, but yours -as you described it- doesn't seem to be one of them.
* Possible solution?
If your purpose is to be able to access remote desktops (RDP) of the network with failed DHCP, then select one of the computers of that network and do the following:
. . . 1. Assign it a fixed IP configuration in the original network, default gateway and DNS included so it never loses connectivity when DHCP is unavailable.
. . . 2. Now add another IP address to the same NIC, this time an APIPA one, e.g., 169.254.0.2. Don't add another default gateway! Keep the one of the original network.
. . . 3. Enable -if not previously done- RDP to that computer.
Now you can access this computer remotely, without changing the DHCP-provided IP address of your computer. Once you've logged at this computer, you can easily use RDP to access the other computers whose IP addresses were provides by APIPA. Be warned that you might have to face some issues by using this scheme.