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LoopBack Issues

Loopback is necessary in some gaming applications and in Opensimulator if you are going to be running on the Hypergrid and using the viewer on the server. The usual symptoms is being unable to log in to the server after switching to a Public IP or a Dynamic DNS name. If your router does not support it, you can install a simple fix to one file so it can run a viewer. The loopback adapter lets a viewer on the server reach itself, as the loopback via the router is not functioning.

Testing for LoopBack

If you are reading this, it is probably because you already know loopback is not working and clicked the Help menu to get here. So you can skip down below and go right to "Installing the Loopback Adapter".

You can manually test for loopback by starting Opensimulator, then use a web browser to navigate to Enter port 8002 and click Check Port. This must work. if not, fix the port forwarding issues and come back and try this test again.

Your ports are known to be working now, so go get the Public IP of your system from Use a web browser to navigate to http://(Public IP):8002. Use your Public IP where it says (Public IP).

You should get a log in page.  If you get this page, loopback is working. If you do not get this page, loopback is not working in your router.

Fixing Loopback

tl;dr:  You need to edit your \etc\hosts file as shown below.

Windows 8 or 8.1 or 10

Search for Notepad, then right-click on Notepad in the search results list, and choose to run it as administrator. If you’re using Windows 10 this will be on the Start Menu.

Once you’ve done so, open up the following file using the File -> Open feature.



Then you can edit as normal.

Windows 7

To access the hosts file in Windows 7 you can use the following command in the Run Line to open notepad and the file.

notepad c:\windows\system32\drivers\etc\hosts


Now enter and then your choice of your domain name separated by a space or a tab character, like this

Editing the hosts file

Now that you have edited your Hosts file make sure to save it.

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