[CentOS] Finding DHCP IP of guest system

If I can log in to the guest through the console, I can of course find out
what IP DHCP has assigned it.  If I configure a static IP I can of course
connect to the system there (if it runs services, the firewall allows it,
all the usual caveats).

Does there happen to be any way to determine from dom0 what IPs are
participating in the network and which guests they belong to?  (I'm
configuring everything as bridged; basically I want to use virtualization
to pretend I have a bunch of independent systems visible to the outside.)

(I suppose just what the IPs are is enough; the number is small enough I
could probe them until I found the system I wanted.  Obviously this is for
use when I'm having trouble getting in through the console but have some
reason to think the rest of the system is alive.)
-- 
David Dyer-Bennet, dd-b at dd-b.net; http://dd-b.net/
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