> Doesn't this second entry conflict with the other CNAME entry? Does
this
> mean you have to have two DNS servers to implement it this way?

If it's in a different zone file, no, because if a user specifies an
unqualified vm1foo01 (which I think is what he's asking for), the
current zone context is assumed, and all proceeds as planned. This
approach (coupled with our convention of hosts that need to do things
like this having a caching DNS installed on the host) also allows
strategic poisoning of the cache to do this sort of magic w/o using host
files. 

Also, it depends on what DNS implementation you use. Many take the last
entry found, some take the first. If you're using bind, I think (no
manuals avail at the moment) it takes the first one. 

If you're really clever, you can also use split horizon support to do
something similar (ie, give a completely different answer depending on
who asks), but not all DNS implementations do a good job of supporting
that. 

> It seems like it would be ok to direct traffic to
> vm1foo01-his0.guest.comeven when the host thinks of itself as
> vm1foo01, but other than confusion
> are there any dragons there?

Depends on whether vm1foo01-hsi0 is actually accessible from the host in
question. This is policy-based routing at it's finest: technically it
may work, but not politically. 

It's a lot harder if the host has to handle mail. The MTA configs in
modern mail delivery will get very cranky and complicated if the
hostname doesn't match what is expected. 

But Mark's other comment is right on -- long term, name the individual
interfaces, and get the users to use the name for the interface they
want if they want policy-based path selection in IP networks. The above
scheme gets complex if there are more than a few aliases. 

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