Re: [Bugme-new] [Bug 8349] New: Manually set IPv6 default route ignored

On Tue, 17 Apr 2007 18:45:12 -0700 bugme-daemon@bugzilla.kernel.org wrote:

http://bugzilla.kernel.org/show_bug.cgi?id=8349

           Summary: Manually set IPv6 default route ignored
    Kernel Version: 2.6.20.7
            Status: NEW
          Severity: normal
             Owner: yoshfuji@linux-ipv6.org
         Submitter: linkfanel@yahoo.fr


Most recent kernel where this bug did *NOT* occur: 2.6.19.5
Distribution: Debian sid
Hardware Environment: x86 (Pentium 4/MMX)
Software Environment: iproute2-ss060323, ifupdown 0.6.8

Problem Description:
Default routes added to the IPv6 routing table, which are not coming from
autoconfiguration, seem to be ignored. Subsequently, IPv6 routing is disrupted,
and for instance calls to connect() fail with an ENETUNREACH error.

Steps to reproduce:
0. Find an IPv6-enabled box on an IPv6-free network. In the absence of any other
configuration, the routing table contains the single line:
fe80::/64 dev eth0 ...
1. Add a default route:
ip -6 ro add default via fe80::1 dev eth0
2. Try to do IPv6, for instance:
# ping6 2001:4978:1:110:0:ac:ce55:1b1e
connect: Network is unreachable
(returns instantly, no packet is sent)

This bug is present in the last stable 2.6.20.7 kernel, and in 2.6.21-rc7. I
actually came across this bug on a server on a network where IPv6 is routed and
advertised, but with autoconfiguration disabled on this server. It *seems* to me
that if the interface is brought up with accept_ra enabled, default routes,
including the one got from RA and ones input by hand later will work, whereas if
it is brought up with accept_ra disabled (or no RA is received), the problem
will occur. Note that routes with a non-null prefix length, such as 3 or 1, work
fine.