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On Fri, Jan 31, 2003 at 01:45:30PM +0000, Philip Hazel wrote:
> On Fri, 31 Jan 2003, Lionel Elie Mamane wrote:
>> The exim IP address parser doesn't recognise IPv6 link-local
>> addresses, like fe80::210:5aff:fe45:9b17%eth0.
> Maybe I have missed something, but I am not aware of things like
> "%eth0" being part of IPv6 addresses.
IPv6 addresses have a notion of "scope", or "size of area where the
address has a meaning". The scopes that are known to me are:
- Global scope: Address is a globally unique address, assigned by
IANA, etc.
- Site scope: Address is valid only within one site (university
campus, ...)
- Link scope: Address is valid on only one wire (physical subnet)
For addresses with link or site scope, there is no guarantee that the
same machine won't have the same address on several of its
interfaces. It is thus necessary to say which one is intended. At the
sockaddr_in6 level, this is given by an integer index in the
sin6_scope_id.
At the textual representation level, on the Unices I'm aware of, this
is done by appending "%name_of_interface" to the colon/hexa
address. I guess that "%numerical_scope_id" would work too, I never
tried.
Do "ifconfig -a" on a FreeBSD box, you'll see these addresses appear:
fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 131.155.140.132 netmask 0xffffff00 broadcast 131.155.140.255
----> inet6 fe80::202:b3ff:fe17:a070%fxp0 prefixlen 64 scopeid 0x2
inet6 2001:610:1108:5010:202:b3ff:fe17:a070 prefixlen 64 autoconf
ether 00:02:b3:17:a0:70
media: Ethernet autoselect (10baseT/UTP)
status: active
Some references I've found by googling around:
http://www.ietf.org/internet-drafts/draft-ietf-ipv6-scope-api-00.txt
http://rfc-2851.rfclist.org/rfc-2851-7.htm
http://www.roguewave.com/support/docs/sourcepro/networkingug/6-6.html (section 6.6.2)
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Lionel
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