Re: [gentoo-user] Link-local ipv6 address in /etc/hosts? in browsers?

[Michael Mol]

On Thu, Jan 19, 2012 at 11:28 AM, Paul Hartman
<paul.hartman+gentoo@×××××.com> wrote:
> On Thu, Jan 19, 2012 at 10:00 AM, Michael Mol <mikemol@×××××.com> wrote:
>> On Thu, Jan 19, 2012 at 10:46 AM, Paul Hartman
>> <paul.hartman+gentoo@×××××.com> wrote:
>>> On Thu, Jan 19, 2012 at 8:43 AM, Grant Edwards
>>> <grant.b.edwards@×××××.com> wrote:
>>>> How do you specify a link-local ipv6 address in /etc/hosts?
>>>>
>>>> For example, I can ping/telnet/ssh to fe80::02c0:4eff:fe07:0005%eth1,
>>>> but I can't figure out how to put that address in /etc/hosts so I can
>>>> access it by name.
>>>
>>> Just put the address without the %iface. Then you must specify the
>>> interface in your program, for example:
>>>
>>> in /etc/hosts:
>>> fe80::02c0:4eff:fe07:0005 foobar
>>>
>>> ping6 -I eth0 foobar
>>>
>>> should work.
>>
>> Works here with ping6. Sucks, though, because most network clients
>> don't allow you to specify the interface, so those won't work.
>
> Yeah, the real solution is like Felix suggests, to use site-local (or
> global) addresses instead of link-local.
>
>>>> Similarly, how do you enter an ipv6 link-local address in Firefox or
>>>> Opera?  curl seems to accept such an address and return the proper web
>>>> page, but I can't find any interactive browser (graphical or
>>>> command-line) that will accept a link-local address.  So far I've
>>>> tried Firefox Opera w3m links. According to RFC2732 it looks like the
>>>> format should be
>>>>
>>>>  http://[fe80::02c0:4eff:fe07:0005%eth1]:80/
>>>
>>> % in a URL must be escaped, so you probably need to replace the %
>>> symbol with %25. Try this:
>>>
>>> http://[fe80::02c0:4eff:fe07:0005%25eth1]:80/
>>>
>>> I didn't try it. Good luck. :)
>>>
>>
>> Doesn't seem to work with wget. Don't have a GUI web browser on IPv6
>> to play with here.
>
> I know MSIE on Windows does (since version 7-ish) and I think wget
> from Busybox does, other browsers/programs are hit and miss...
>
> According to RFC 3986:
>
> "A host identified by an IPv6 literal address is represented inside
> the square brackets without a preceding version flag.  The ABNF
> provided here is a translation of the text definition of an IPv6
> literal address provided in [RFC3513].  This syntax does not support
> IPv6 scoped addressing zone identifiers."
>
> Key being the last sentence. :) So, some browsers support that syntax,
> but it's not required. So I would not depend on that feature existing.
> Best to avoid using those addresses for web stuff if you can help it.
>

Indeed. Other reasons to avoid using LL addresses unless necessary:
What if the MAC address on the server changes? What if your network
grows to have hundreds of clients? Do you really want that much
broadcast and wide multicast (think DNS-SD and  NTP in multicast mode)
traffic on the same Ethernet segment?

Flameeyes discovered an oddity with ethernet/wifi bridges which broke
node solicitation, too.

LL addresses are very useful for diagnostic and investigation
purposes, of course.

-- 
:wq