using named with CARP

[Malcolm Herbert <mjch%mjch.net@localhost>]

As far as I can recall, an application (such as named) cannot bind
directly to a CARP-managed virtual IP and listen for connections. Is
this the case?

I've seen CARP virtual IPs used to provide reliable routing services for
a network but haven't seen them in use with an application listening on
them directly, hence the question ...

My thoughts for getting around that restriction (if it exists) would be
to have the application listen on lo0 and configure pf to redirect or
NAT incoming connections on the CARP VIP to the application on lo0.

This sounds like it should work, although it seems to be a lot of extra
effort to me ... is it really necessary?

Can an application cope with having an IP interface suddenly disappear
or re-appear after it has started? Or am I simply making things too hard
for myself and everything should Just Work if the application binds to
all network interfaces?

What would I do in situations where I want the application to bind to
the CARP interface only and then can't make use of the dynamic nature
of an 'all interfaces' bind? I guess I could use pf to drop incoming
connections from those interfaces I'm not interested in if this were the
case ...

Has anyone set up CARP in this manner with applications listening on
the CARP VIP?

Regards,
Malcolm

-- 
Malcolm Herbert                                This brain intentionally
mjch%mjch.net@localhost                                                left 
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