(usagi-users 03414) Re: Source address for neighbor solicitations

On Wed, Jun 22, 2005 at 07:32:57PM +0900, thus spake Noriaki TAKAMIYA:
> => in case a router doesn't, shouldn't it use any global address available to
> => send the NS instead of just silently failing?
> 
>   The following will help this:
> 
>   In RFC2461:
> --------------------------------------------------
> 4.3.  Neighbor Solicitation Message Format
> :
>    IP Fields:
> 
>       Source Address
>                      Either an address assigned to the interface from
>                      which this message is sent or (if Duplicate Address
>                      Detection is in progress [ADDRCONF]) the
>                      unspecified address.
> :
> 7.2.2.  Sending Neighbor Solicitations
> :
>    If the source address of the packet prompting the solicitation is the
>    same as one of the addresses assigned to the outgoing interface, that
>    address SHOULD be placed in the IP Source Address of the outgoing
>    solicitation.  Otherwise, any one of the addresses assigned to the
>    interface should be used.  Using the prompting packet's source
>    address when possible insures that the recipient of the Neighbor
>    Solicitation installs in its Neighbor Cache the IP address that is
>    highly likely to be used in subsequent return traffic belonging to
>    the prompting packet's "connection".

This is actually not what happens : if the source address of the packet
prompting the solicitation is not one of the addresses assigned to the
outgoing interface, the solicitation is not sent at all.  I understand from
the above that it should then use _any_ address available.

-- 
A person is shit's way of making more shit.
		-- S. Barnett, anthropologist.