[Opensim-users] NAT & Corporate Firewall

[Gary Beck]

Diva Canto wrote:
> DNS resolution is made by the client. The server simply passes the name 
> over. Make sure to use domain names consistently in all configuration 
> files.
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My testing seems to show the IP address rather than domain name is passed to 
the client for region/UDP.

I have one region using ExternalHostName=SYSTEMIP and the others using 
ExternalHostName=something.dyndns-mail.com
I run Opensim 0.7.0.2 on a VISTA system, stand alone mode, client access 
both local and external, NAT loopback on.
All that works fine.

To test I added a HOSTS file entry on the server PC using 127.0.0.1 for 
something.dyndns-mail.com.
With that change I was able to login a client on the server PC without 
issues.
Logging in from a local non-server PC I cannot start at or TP to a region 
that has ExternalHostName=something.dyndns-mail.com.  Login fails at the 
handshake step.  However, I can login on that PC starting at the region with 
ExternalHostName=SYSTEMIP.   Handshake works.

I interpret all that to mean the server is sending the IP address to the 
client for the UPD communication.  If the server was passing the domain name 
I would expect no Client issues on my non-server PC.  I'm only changing the 
IP address of my ...dyndns... domain name on the server PC for this test. 
In fact, I can remove the HOSTS entry while the server continues to run. 
After that I can again login on a local/non-server PC with no problems.

One other item I found that suggests IP addresses are being passes rather 
than domain names is the Entity Transfer Module entries in the server log
2011-04-04 22:24:53,759 INFO  - 
OpenSim.Region.CoreModules.Framework.EntityTransfer.EntityTransferModule 
[ENTITY TRANSFER MODULE]: Starting to inform client about neighbour 999, 
999(174.124.181.36:9009)

Network isn't my specialty so I may have misinterpreted things.  I welcome 
other explanations.

(Multimedia seems to be handled by passing the domain name - but that's 
another story.)