query-source for multiple interfaces

[Barry Margolin]

In article <e4gd1a$4bm$1 at sf1.isc.org>,
 Mark Andrews <Mark_Andrews at isc.org> wrote:

> > In article <e4feh9$12k9$1 at sf1.isc.org>,
> >  Sam Wilson <Sam.Wilson at ed.ac.uk> wrote:
> > 
> > > Looking at the ARM the "query-source" option seems to be able to specify 
> > > only one address.  We are investigating anycast DNS on multihomed 
> > > servers.  It looks as though I can't use "query-source" to allow queries 
> > > to be sent from any address except the multicast address.  Is this true 
> > > and is there any obvious workaround?  I've already thought of adding a 
> > > second local /32 address that's specific to the box and sourcing the 
> > > queries from there, but that's getting rather messy.
> > 
> > If the anycast address is an alias IP, I don't think you need to do 
> > anything.  I think the OS will automatically default the source address 
> > to the primary IP of the outgoing interface rather than an alias.
> 
> 	Also it does not make sence to send queries from a anycast
> 	address as the replies are not guarenteed to go back to the
> 	correct instance.

That's his point -- he wants to PREVENT it from using the anycast 
address.  But he doesn't want to list all the other addresses 
explicitly, he was hoping for something like:

query-source address { !1.2.3.4; };

to mean "use any of the system's addresses except 1.2.3.4".

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
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