On Thu, Jun 17, 2004 at 08:13:47AM +0300, Pekka Savola wrote: > On Wed, 16 Jun 2004, Bernd Eckenfels wrote: > > In article <1087370535.24446.2981.camel@segesta.zurich.ibm.com> you wrote: > > >> If the application prefers ipv6 it will try to use them, and only on connect > > >> it receives an error. Some do then ipv4 fallback (lynx) some dont (mozilla). > > > > > > Fix your routing as that is the problem. > > > > No it is not, a Host with only link-local addresses is perfectly well > > configured. The application can actually bind to the family and try to > > connect to the internet destination, it will just have to deal with the net > > not reachable error. And some applications dont. (but this is actually only > > the reson why i ave looked at the sysctl options, even if all aplications > > are fixed the options still behave wrong) > [...] > > I think we may be having a slightly different problem here (as what > the others are discussing). When you have enabled IPv6 but the > network does not support IPv6 (i.e., you have link-local addresses), > there are certain problems which may lead to longer timeouts. This > depends principally on (at least) two things: > > 1) whether the node has a "on-link assumption", i.e., a default route > to your interface. > > 2) whether TCP implementation aborts connection when it receives a > "soft" ICMP error (against the host requirements RFC), > > These are both described at some length in > http://www.ietf.org/internet-drafts/draft-ietf-v6ops-v6onbydefault-02.txt > > The key point here is that in these cases, even if the application was > properly programmed, you might need to wait for a long time (dozens of > seconds, even minutes) before the application would fall back to IPv4. > > IMHO, Linux should do both: > 1) remove the IPv6 default routes pointing on each interface when the > interface is created, They key is, there is no default route, unless its autoconfigured, in whcih it should have one.... > 2) abort TCP connections which are in SYN-SENT state when an ICMP > error is received. > > This would help the robustness a lot in the scenarios where you want > to enable IPv6, and make sure it works, even if you didn't have IPv6 > connectivity. > > I.e., this is a critical thing for vendors which might want to ship > with IPv6 enabled by default. > > -- > Pekka Savola "You each name yourselves king, yet the > Netcore Oy kingdom bleeds." > Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings > > > > - > : send the line "unsubscribe linux-net" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Trent Lloyd <lathiat@bur.st> Bur.st Networking Inc. - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
