[avahi] Mutli-homed server problem

[Stuart Morris]

Ladies and Gentlemen,

I've got a problem that is driving me nuts. I'm very experienced at  
*nix sysadmin and IP networking but until this morning I had never  
touched any zeroconf stuff. After spending the morning evaluating the  
various zeroconf offerings I decided upon Avahi. It was certainly the  
easiest to set up and the most logical to configure except for my  
problem:

The machine I am running Avahi on (local name "ruth") has two IP  
addresses: eth0 is a "real world" ip (e.g. 81.82.83.84) and eth0:1 is  
a private address (e.g. 192.168.0.84).
Avahi appears to bind to both addresses. If I publish a web service  
it shows up as ruth.local. but insists on returning the 81.82.83.84  
IP address. As the service I'm trying to publish is for internal  
consumption only and the web server is only listening on the internal  
IP I really want it to return the internal IP.

So here is the question... How can I force Avahi to bind only to one  
of the network devices and/or how can I force it to return the  
internal IP address for ruth.local. ?

Or, have I misunderstood some fundamental zeroconf/Avahi principle?

Many thanks,

Stuart