[radvd-devel-l] Advertising interface is not "autoconfigured"

Nathan Lutchansky radvd-devel-l@litech.org
Thu, 24 Jan 2002 17:53:51 -0500 (EST)

Hash: SHA1

On Thu, 24 Jan 2002, Venkata Jagana wrote:

> On this very topic, Pekka and I exchanged several emails more
> than 6 months ago and obiviously, there are disagreements on
> whether router interfaces need to be autoconfigured or not.

I thought this was discussed on the IPng list a while back, and the
conclusion was that autoconfiguring routers is too hairy to be a good
idea.  I certainly would never want to do it with my own routers.

> If they should't be autoconfigured then in manual configuration, what
> prefixes would be used to configure those interfaces. Wouldn't they
> be same as the prefixes advertised by radvd on the respective interfaces?

Generally, but not necessarily.  There may be "hidden" prefixes in use on
the link that only the router and certain hosts are aware of, which would
obviously need to be configured manually.

> Looks to me that it is purely an implementation and startup issue.

I wouldn't think it was purely an implementation issue.  If routers
autoconfigured, it would be fairly easy for a renegade host to advertise a
bogus prefix, which the router would add to its prefix list for the link,
and possibly propagate the bogus route through the rest of the site.

> In fact, I believe (based on old email on this topic on netdev) the
> KAME stack doesn't seem to even accept or autoconfigure addresses for
> router interfaces based on RA's received from other routers. But that's
> not the case in radvd for Linux either. Radvd daemon on Linux is
> disallowing autoconfigration with the advts from the same router but
> not from other routers if forwarding is enabled and I believe this is
> inconsistent.

I'm fairly sure this isn't true.  Linux, like KAME, ignores *all* rtadv
messages regardless of the source if forwarding is enabled.  -Nathan

- -- 
| Nathan Lutchansky | lutchann@litech.org |  Lithium Technologies  |
|  I dread success.  To have succeeded is to have finished one's   |
|  business on earth...  I like a state of continual becoming,     |
|  with a goal in front and not behind. - George Bernard Shaw      |
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