APIPA address and the internet

Question

Hello I just wanted to get something clear. If a computer gets a APIPA address for whatever reason, it will not be able to get on the internal network and the internet? Is that correct?

Answer 1

From RFC3927:

An IPv4 packet whose source and/or destination address is in the 169.254/16 prefix MUST NOT be sent to any router for forwarding, and any network device receiving such a packet MUST NOT forward it, regardless of the TTL in the IPv4 header.

A device with a APIPA address will not have any default gateway, and will not be able to send any packets beyond it's local subnet (the 169.254/16 subnet).

The only reachable devices will be hosts on the same broadcast domain that also have been assigned APIPA addresses.

Answer 2

Almost correct: It will not be able to connect to the internet, as these IP ranges are blocked on the core switches of the Internet Exchanges. However, if another system also gets an (APIPA) IP-address in the same subnet (169.254.X.X) then those two systems can communicate to eachother.