#17510: /60 rather than /64 IPv6 'interface' route created on LAN interface
-----------------------------+-----------------------------------
Reporter: markzzzsmith@… | Owner: developers
Type: defect | Status: reopened
Priority: normal | Milestone:
Component: base system | Version: Barrier Breaker 14.07
Resolution: | Keywords:
-----------------------------+-----------------------------------
Comment (by markzzzsmith@…):
I'd need to understand the problem better to comment on it. It seems
you're saying that if you delete an IPv6 address from an interface, the
automatically created /64 hangs around?
While on face value that would seem incorrect, however it is quite
possible for a device to know a /64 prefix is on-link but not to have any
addresses from within it. Alternatively, it is possible for a host to have
an address from within a /64, but to assume all other destinations within
that /64 are off-link (with exception to the link-local prefix) This is
better explained and clarified in:
IPv6 Subnet Model: The Relationship between Links and Subnet Prefixes
http://tools.ietf.org/html/rfc5942
This actually makes the assumption of a /128 when adding a static address
via 'ip -6 address add <blah>' with no prefix specified consistent with
that RFC. It specifically states that configuring a static IPv6 address on
an interface should not automatically create an assumed /64 on-link prefix
route.
One other thought in this area. I think there are three separate IPv6
related addressing functions:
- address or rather IID generation methods - e.g., use MAC address, or
hash as per RFC7217 opaque IDs
- address configuration methods - currently SLAAC, DHCPv6 or static
- address expiry methods - currently address aging via preferred and valid
lifetimes
If you're having trouble with the last one, one trick would be to manually
set the preferred and valid lifetimes to deprecated values, so that the
host avoids using them if there are better addresses to use, as per
RFC3484/RFC6724.
--
Ticket URL: <https://dev.openwrt.org/ticket/17510#comment:8>
OpenWrt <http://openwrt.org>
Opensource Wireless Router Technology
_______________________________________________
openwrt-tickets mailing list
[email protected]
https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-tickets
