>>>>> On Fri, 29 Jun 2001 06:12:28 +0900 (JST),
>>>>> Hajimu UMEMOTO <[EMAIL PROTECTED]> said:
oberman> I agree, but I have made no deliberate changes. I just install FreeBSD
oberman> with ipv6_enable="YES" in rc.config.
oberman> Internet6:
oberman> Destination Gateway Flags Netif Expire
oberman> :: localhost UGRSc lo0 =>
oberman> default fe80::1%lo0 Uc lo0
> Why are you set ipv6_enable to YES while you are not using IPv6? :-)
> I just could reproduce your problem. When no RA is available, default
> route is wrongly installed by `ndp -I'.
> Please set ipv6_default_interface to NO in your rc.conf. Current its
> default setting is meaningless in most cases and it is harmful. I'll
> change default of ipv6_default_interface to NO.
Please let me explain the rationale. The notion of
"ipv6_default_interface" is introduced mainly for conformance to the
following part of RFC 2461:
Next-hop determination for a given unicast destination operates as
follows. The sender performs a longest prefix match against the
Prefix List to determine whether the packet's destination is on- or
off-link. If the destination is on-link, the next-hop address is the
same as the packet's destination address. Otherwise, the sender
selects a router from the Default Router List (following the rules
described in Section 6.3.6). If the Default Router List is empty, <---
the sender assumes that the destination is on-link. <---
That is, if we do not have any default router (hear from RA), we
should regard all IPv6 prefixes as on-link. To implement this trick,
we use the "default interface", and install the default route as an
interface direct route to the interface.
However, as shown in this thread, this feature is basically
meaningless, and even harmful, especially when using IPv4 as well.
Thus, for the moment, I agree that we should turn the default
interface off by default. For a longer term solution, we might have
to consider a better source address selection algorithm,
e.g. described in draft-ietf-ipngwg-default-addr-select-04.txt. Then
IPv4 would be preferred in this case.
JINMEI, Tatuya
Communication Platform Lab.
Corporate R&D Center, Toshiba Corp.
[EMAIL PROTECTED]
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