I have incorporated a patch from user Jamie Walker <jamie@sagaxis.co.uk>,
which allows you to disable DNS lookups.  Jamie says:

"Orbit always encodes the server's hostname in the ior. This breaks
IIOP if any clients do not have the DNS configured properly. I enclose
a patch to add a command line option, ORBIIOPIPv4NoDNS, to force the
IP address to be used instead of the hostname. This fixes the problem
on our WAN, and also keeps the original behavior as default."

At the moment, this patch has not been incorporated upstream, but the
initial reaction on the orbit developers list has been entirely
positive.  However, it is possible that the patch will be changed when
(and if) upstream does incorporate it.  (For example, they might
remove the "IPv4" part, and make it work for v4 and v6.)  So, some
caution should be used when deciding if you want to depend on this
feature.