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Re: source address selection

To: kuznet@xxxxxxxxxxxxx
Subject: Re: source address selection
From: Artur Frysiak <wiget@xxxxxxxxxxxxxxxxxx>
Date: Wed, 29 Dec 1999 10:54:49 +0100
Cc: "Takeshi Kusune / ?$@Fo:,M:;V?(J" <kusune@xxxxxxxxxxxxxx>, netdev@xxxxxxxxxxx
In-reply-to: <199912161609.TAA07161@xxxxxxxxxxxxx>; from kuznet@xxxxxxxxxxxxx on Thu, Dec 16, 1999 at 07:09:31PM +0300
Mail-followup-to: kuznet@xxxxxxxxxxxxx, "Takeshi Kusune / ?$@Fo:,M:;V?(J" <kusune@xxxxxxxxxxxxxx>, netdev@xxxxxxxxxxx
References: <199912152351.IAA05354@xxxxxxxxxxxxxxxxxxxxx> <199912161609.TAA07161@xxxxxxxxxxxxx>
Reply-to: Artur Frysiak <wiget@xxxxxxxxxxxxxxxx>
Sender: owner-netdev@xxxxxxxxxxx
On Thu, 16 Dec 1999, kuznet@xxxxxxxxxxxxx wrote:

> Hello!
> 
> > BTW, I think that Linux's current IPv6 code is not enough to work with
> > multi-addressed network, because of weakness in source address selection.
> 
> The patch is good and correct, but the solution is bad.
> 
> We may make this thing in IPv4 because function inet_select_addr()
> is not in data path; selected source addresses are stored in routing tables.
> Correct solution would cache once found source address
> in IPv6 routing table, probably, cloning route, if it is required.
> 
> BTW we have to make this thing in IPv4 because by historical reasons
> internet routing is very messy and smart source selection is required
> to route replies back. Moreover, by the same historical reasons, almost
> all IP apps are confused, when loopback address appears as source
> address of packet destined to some address of the host.
> Emerging IPv6 principles should not inherit all of this brain damage,
> so that the problem is present but it is not critical.

Source address selection for IPv6 is very useful feature.
I give one real example:
I use zebra as routing daemons. My machine has 2 IPv6 address at eth1 (internal
LAN). I must set both address as neighbor in BGP4+ config in other machine in 
LAN 
to get zebra to work. If I may select source address then I may set only one 
neighbor.

Wiget
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