Better control over what mDNS announces

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

I'm used to having control over my DNS. If server X provides service Y for 
clients in a certain net, the DNS view for these clients announces server 
X's address that clients can reach.
With CUPS having abandoned its own browsing protocol (which worked perfectly 
for our use case) I suddenly find myself in the Wonderful World of 
Bonjour/Rendez-vous/Allez-hop and things automagically going wrong in 
convoluted ways (like the client trying to contact the CUPS server on an 
IPv6 interface that's not really operational or on an IPv4 alias that's 
only used for DNS).
So I'm thinking about implementing some mdnsd/mDNSResponder options to 
re-gain some control over what it announces. I haven't looked into how 
feasable each option is; but I would like some comments, especially from 
mDNS experts, if possible.

-- If the only IPv6 address on an interface is link local, regard that 
   interface as not set up vor IPv6 (and don't announce the LL address).

-- Don't announce link local addresses at all.

-- Don't announce any alias address, only the main one.

-- Ignore a given list of interfaces (or only serve a given list)

Comments, anyone?