ipv6 hosts name resolution

Question

Greetings everyone,

I'm trying to get ipv6 name resolution working using hosts file. It works ok for IPv4 addresses but I've tried many formats for and still can't get it to translate IPv6 hosts, see below my attempts:

fe80::10:18ff:fe99:9904 Machine1
fe80.0000.0000.0000.0010.18ff.fe99.9904 Machine2
fe80::210:18ff:fe96:3f66 Machine3
fe80:0000:0000:0000:0210:18ff:fe96:3f66 Machine4
fe80::21:70ff:fe9b:9925 Machine5
fe.80.00.00.00.00.00.00.00.21.70.ff.fe.9b.99.25 Machine6
fe-80-00-00-00-00-00-00-00-0c-29-ff-fe-c4-2f-f0 Machine7
192.168.1.100 Machine8
2.2.2.1 Machine9
2.2.2.2 Machine10

Regards - Philippe

Answer 1

According to the prefix fe80, these are all IPv6 link-local addresses. You should use the global or site-local addresses instead.

In an IPv4 address, the subnet mask specifies which part of the address is the network ID. A multi-homed system will have a different network ID for each interface. IPv6 link-local addresses, on the other hand, all have the same prefix. Therefore, the address by itself, is not sufficient to determine which interface should be used for link-local traffic.

See IPv6 address - Link-local addresses and zone indices which has a brief explanation of why the IPv6 address of an interface by itself is not sufficient for the local computer to make a routing decision and discusses the use of a zone ID to differentiate the interfaces.

Also see TCP/IP Fundamentals for Microsoft Windows Chapter 7 - Host Name Resolution. Microsoft states "For IPv6 entries, the address in the Hosts file entry is a global or site-local IPv6 address expressed in colon hexadecimal notation."

Then there is an example of a Hosts file with both IPv4 and IPv6 entries (but no link-local addresses).

Followed by "You should not place entries for link-local addresses in the Hosts file because you cannot specify the zone ID for those addresses."