Messages in this thread | | | Date | Wed, 28 May 2008 11:59:45 +0200 | From | Pascal Hambourg <> | Subject | Re: Wired behaviour with IPv6 over PPP |
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Hello all,
Willy Tarreau a écrit/wrote : > On Thu, May 22, 2008 at 09:05:47PM +0200, Matthias Cramer wrote: > >>James Chapman wrote: >> >>>Andrew Morton wrote: >>> >>>>On Wed, 21 May 2008 14:56:43 +0200 Matthias Cramer >>>><matthias.cramer@interway.ch> wrote: >>>> >>>>>I have a very wired behaviour when doing IPv6 over PPPoE. >>>>> >>>>>The situation: >>>>> >>>>>A linux box connected to a DSL Modem, on the other side is a Cisco >>>>>LNS which terminates the PPP session (actually L2TP). >>>>>I have control over both ends. >>>>> >>>>>When I have net.ipv6.conf.all.forwarding set to 0 then the ppp >>>>>Interface gets a IPv6 address from the Cisco via IP6CP. >>>>>When I have net.ipv6.conf.all.forwarding set to 1 them the ppp >>>>>Interface does not get an address, it has only a normal link local >>>>>address.
AFAIK IPV6CP/PPP only allows to negotiate link local addresses. So I guess the global address and default route is assigned by another mechanism, maybe stateless autoconfiguration using router advertisement, although I was not aware it could be used on a PPP link because of the absence of MAC address. Enabling global forwarding (net.ipv6.conf.all.forwarding=1) disables stateless autoconfiguration (see ip-sysctl.txt in kernel documentation) on all interfaces. I believe this is consistent with the observed behaviour.
>>>>>When I start the ppp session with forwarding set to 0 I can ping out >>>>>and there exists a default route to ppp0 , then I switch forwarding to 1 >>>>>the default route disappears and therefore routing does not work any >>>>>longer.
I have read reports about this. I guess the logic is that enabling forwarding turns the box into a router, so the default route learned from another router's advertisements by autoconfiguration should be deleted. Even the autoconfigured global address will eventually expire.
> Well, at least it has been working for years in kernel 2.4 for me with > pppd 2.4.2b3 to 2.4.4 (I've not upgraded my firewall to 2.6 yet). So > it has definitely been working at some point.
What exactly has been working ?
PS : Willy, do you plan to backport the security fix for the sit module from 2.6.25.3 into 2.4 ? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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