[Opensim-dev] Global identifiers

[Ai Austin]

In OpenSim references to host names , we seem to see three different 
types of host address:

IP numbers
DNS names
DNS names of an underling machine

OpenSim allows the specification of host name is used for the various 
(Robust) services, but still we often see it subsitituted with the 
underlying IP address, and in one or two cases perhaps the underlying 
canonical DNS machine name.

Our policy is always to specify a (stable) DNS alias (CNAME) for what 
we call a service name  e.g. ftp.aiai.ed.ac.uk, ssh.aiai.ed.ac.uk, 
xmpp.aiai.ed.ac.uk, media.aiai.ed.ac.uk, and then map that to the 
current host that provides that service.  The underlying canonical 
host name is unique in our asset data base, so cannot easily be 
reused when we move to new hardware.

Hence, for our virtual worlds servers we have used aliases as follows:

virtual.aiai.ed.ac.uk for the entry grid services (Robust in our case)
virtual1.aiai.ed.ac.uk  for an OpenSim region server
...
virtualN.aiai.ed.ac.uk  for an OpenSim region server

If the "authority" in the external identity URL is to have any 
meaning at all in our context, and stand a chance later of finding 
the machine running the relevant virtual worlds services, it needs to 
retain the name we give for the services in the OpenSim.ini and 
Robust.HG.ini files... not try to resolve that to a current mapping 
to an IP number or an underlying machine name.

I would assume similar issues would arise if dynamic server name 
services are used to get a stable name for using OpenSim in some home 
and NAT router network situations too.