kern/143705: [stf] the should be a way to support multiple 6to4 addresses

[Lapo Luchini]

>Number:         143705
>Category:       kern
>Synopsis:       [stf] the should be a way to support multiple 6to4 addresses
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Feb 09 18:50:01 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Lapo Luchini
>Release:        FreeBSD 8.0-STABLE amd64
>Organization:
>Environment:
System: FreeBSD deepie.home.lapo.it 8.0-STABLE FreeBSD 8.0-STABLE #21 r203605: Sun Feb  7 15:18:51 CET 2010     root at deepie.home.lapo.it:/usr/obj/usr/src/sys/DEEPIE  amd64

>Description:

(I'm a bit undecided if this is a doc-bug or a change-request, but I think the former is certain, the latter could be useful.)

Let me explain: when a server changes IPv4 it can (in some cases) have both as aliases for a while, so that the change does not imply downtimes.

Using 6to4 this does not appear to be the case: interface stf1 can't be created (and this is the documentation bug: "man stf" states that "Each stf interface is created at runtime using interface cloning") and adding an alias address to the existing stf0 interface does no effect at all: only the first address is used (and this is the change request: either support both address or maybe forbid adding a second alias, if that's possible).

In reference (and a bit more verboseness), two messages by myself in the freebsd-net mailing list:
http://lists.freebsd.org/pipermail/freebsd-net/2009-March/021271.html
http://lists.freebsd.org/pipermail/freebsd-net/2009-July/022591.html
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