EUI-64 uses the NIC MAC to derive an address. Linux by default uses it, and it's fine for servers.
There are other more privacy sensitive ways to generate obfuscated addresses.
But none of these matter, because RFC 4941 says a new random address is used for each request. If you surf the web on a server with a static address, it'll create hundreds of temporary, random addresses to make requests from. The server is reachable by the static address, but outgoing requests come from a random address.
I know, weird, right? Concept 2: IPv6 uses multiple addresses.
Yes, if you replace the NIC, the address will change. Different OS won't, if it uses EUI-64.
There are other more privacy sensitive ways to generate obfuscated addresses.
But none of these matter, because RFC 4941 says a new random address is used for each request. If you surf the web on a server with a static address, it'll create hundreds of temporary, random addresses to make requests from. The server is reachable by the static address, but outgoing requests come from a random address.
I know, weird, right? Concept 2: IPv6 uses multiple addresses.
Yes, if you replace the NIC, the address will change. Different OS won't, if it uses EUI-64.