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(usagi-users 01209) Re: Is this a bug?



On Thu, Jan 24, 2002 at 06:58:31PM +0200, Pekka Savola wrote:
> On Thu, 24 Jan 2002, Nathan Lutchansky wrote:
> > > How badly would you have to much up your routes to get into this 
> > > situation?  How many *real* (non-erroneous) usage scenarios are there?
> > 
> > This should apply to any p-t-p link; I see no reason to assign global 
> > addresses on p-t-p interfaces if the nodes on each side have global 
> > addresses assigned on other interfaces.  -Nathan
> 
> Note that this question was about the global destination address: I don't
> think it's necessarily the best practise to select a link-local source for
> that.

I don't think it is good practice to use a link-local source for *any* 
communication, unless the destination is also link-local.  Using 
link-local addresses breaks things like DNS reverse lookup, and 
personally, when I'm coding applications, I expect to be working only with 
global addresses even though I never explicitly check that this is so.

However, I haven't read the source address selection draft, so my above 
point could be either obviously correct or horribly wrong.

> Issues:
>  - if you try to reach the either end of p-t-p, link-local source is fine

From a layer-3-only point of view, this is correct.  But as I mentioned, 
applications might get confused if one endpoint is link-local and the 
other is global.  I believe this is of greater importance than choosing an 
address from the correct interface.

>  - if you try to reach any other address, link-local is not fine (would be
> silently discarded when forwarding unless explicit route is added to e.g.
> loopback address in the sending node).

Of course.  -Nathan

-- 
+-------------------+---------------------+------------------------+
| Nathan Lutchansky | lutchann@xxxxxxxxxx |  Lithium Technologies  |
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|  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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