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Engaged Sweeper II

I'm busy troubleshooting a couple of servers that are giving us "The RPC server is unavailable 0x800706BA" errors using the Lansweeper guide. I checked all the usual things, firewall, DCOM, etc. and everything was fine.

So I asked our netadmin to check what was being blocked and it seems we needed to open port 4345 for the scan to work. Once we did this, it was fine. But why this port?

When I tried another server that wasn't scanning, we got a similar error, this time for port 4516. Any idea why this is happening?


Engaged Sweeper II
Thanks for the quick response. It turned out to be the network firewall allowing port 135 but not the dynamic port range WMI uses for data. Once we fixed that everything was fine.
Lansweeper Alumni
For an overview of ports used by Lansweeper, please refer to this knowledge base artilce.

After the initial WMI session has been established, WMI data is transmitted using random ports.
- Firewalls tend to have specific settings to allow WMI traffic. We recommend reviewing the documentation for your specific firewall.
- You can also set up a fixed port, though this is somewhat involved. Configuring a static port must first be done on the client machines you wish to scan. You will then have to open the chosen port on your firewall as well.
- Another option is to scan using LsPush, which circumvents most firewall issues.