Opensim not working? Some basic things to check:

Someone on metro was having problems so I started to write out a checklist of things to go over when running opensim. The list snowballed so I thought it would be worth sharing as a blog. Here ya go!


If you are able to start opensim but not connect to metro, or not connect to the hypergrid, try looking at these issues and seeing if you can fix them.

First -there’s two ways computers communicate with each other; tcp and udp. This is important to remember.

First thing to check; windows firewall. You will need to make a rule that allows incoming and outgoing traffic on ports 8000-8003. You need to make one set of rules (incoming and outgoing) for udp and one set for tcp.

You will need to make rules in windows firewall for port 9000 (udp and tcp) and you’ll have to make rules for each region in addition that you want to host. Personally, I make a rule opening ports 9000-9200 (tcp and udp); I don’t use all of those but if I need them, they’re open.

Then your hardware firewall. You’ll have to read the manual or google for your router model, but usually most modems have a way to open ports; you’ll want to find out how to do this on your router and then open the same ports that you did for windows firewall.

If you have a home network (IE  you share the internet with family, spouse, other computers) make sure that the opensim traffic is going to the right place. Find which **LOCAL** IP your machine is getting assigned to by the router and then find out how to direct traffic to that IP so that the router doesn’t send it to the wrong computer or drop it entirely. On belkin routers that’s under the “virtual servers” link; your router will be different and you’ll have to google/read the manual about network redirection.

Loopback. Most home routers don’t support loopback (virtual network adapter) and that can cause viewers to hang when trying to connect to a local opensim instance. The best way to cope with this currently is to create a virtual loopback device; the instructions for that will differ depending on your operating system, and operating system version. Look here for a general idea:

If none of these pan out, then ask your grid for support on their forum (for example, to get metro’s version running, go to and descripe your setup, describe the steps you took and describe what problems you’re having as in as much detail as possible).

Published by: hanheld

I'm a virtual world resident; I build, blog and play with server software (these days, largely opensim).