IPv6 router advertisement

Michael H. Warfield mhw at WittsEnd.com
Wed May 6 22:33:06 UTC 2009

On Wed, 2009-05-06 at 15:00 -0500, Ted Lemon wrote:
> On May 6, 2009, at 2:34 PM, Mihai Moldovan wrote:
> >> Given the symptoms you're describing, my working theory is that
> >> Microsoft's autoconf implementation is synthesizing the default route
> >> using the source address of the RA message, and Linux is not.
> > Sorry for asking such a stupid question, but isn't this was RA is
> > actually meant to be used for? Or where does Linux get the router
> > address from?
> This is what I get for speculating without reading the RFC.   Here's  
> what RFC 4861 says:
> On receipt of a valid Router Advertisement, a host extracts the source  
> address of the packet and does the following:
> - If the address is not already present in the host's Default Router  
> List, and the advertisement's Router Lifetime is non- zero, create a  
> new entry in the list, and initialize its invalidation timer value  
> from the advertisement's Router Lifetime field.
> - If the address is already present in the host's Default Router List  
> as a result of a previously received advertisement, reset its  
> invalidation timer to the Router Lifetime value in the newly received  
> advertisement.
> - If the address is already present in the host's Default Router List  
> and the received Router Lifetime value is zero, immediately time-out  
> the entry as specified in Section 6.3.5.

> So to me this means that the behavior you are seeing is wrong.    
> What's the steady-state value of net.ipv6.conf.all.autoconf on your  
> linux machine?   Also, do you have any kind of firewall setup on  your  
> linux machine?

	Also...  What is the value of net.ipv6.conf.all.forwarding?  If that is
set to 1, autoconf is automatically disabled.

> I'm running 2.6.29 right now, but I've run with earlier versions of  
> the kernel on a /64 and not seen this problem.

Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
   NIC whois: MHW9          | An optimist believes we live in the best of all
 PGP Key: 0xDF1DD471        | possible worlds.  A pessimist is sure of it!

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 307 bytes
Desc: This is a digitally signed message part
URL: <https://lists.isc.org/pipermail/dhcp-users/attachments/20090506/ba2e6172/attachment.bin>

More information about the dhcp-users mailing list