Creating a Hosting session with a couple users is usually not really hard but it can become really tricky when you start being more than 4 pilots on the Hosting server with limited bandwidth.

So how do we handle the network settings and how do we make sure your BMS experience is great?

Understanding the Network settings

 The ports NAT/PAT settings

For BMS Server you need the following settings on your router (internet box):

  • Rule Name: “BMS Server”
  • Protocol: UDP
  • Internal ports range: 2934-2935
  • External ports range: 2934-2935
  • Source: ALL (
  • Destination: Your BMS server local IP

For IVC Server you need the following settings on your router (internet box):

  • Rule Name: “IVC Server”
  • Protocol: UDP
  • Internal ports range:9987-9989
  • External ports range:9987-9989
  • Source: ALL (
  • Destination: Your IVC server local IP

If you need to test your UDP connectivity on the Falcon BMS side, you can try this tool F4testPort (this tool is provided as is and not supported by us…)


The Bandwidth settings

This section is really key to start troubleshooting your connection troubles…

Right now, Falcon BMS requires at least 1024 Kbit/s to secure a single client feedback. So if your upload bandwidth is lower than that, consider dealing with issues or start thinking about upgrading your ISP…

Falcon BMS 4.33 Bandwidth usage

Falcon BMS 4.33 Bandwidth usage

As shown in the figure above (chart from BMS manual), Falcon BMS 4.33 requires an average of 850 Kbit/s with some spikes to 1024 Kbit/s… Anything lower than that will cause the client / server to skip some data to preserve the bandwidth limit set by the user.

If you are lucky and have more than 1M upload, then set it to Max 70% of your upload capacity… Use if you need to check that!


The Falcon BMS config file

There are some hidden settings in the Falcon BMS code that can tweak the way clients and servers communicate together…

In the “Falcon BMS.cfg” file (/user/Config/) you will find the following settings:

set g_bServerHostAll

This setting must remain to 1 if you wish your MP session to maintain data consistency since all datas impacting the TA / Campaign are sent to server to be redistributed to other clients.

set g_nForceMinClientBwSetting

As you should have understood by now, this setting should be at a minimum of 1024 to ensure client good transmission rate…

Set g_bClientServerConnection

This setting does not exist by default in the config file and you have to add it in the MP section of the configuration file…

This basically force the connection to exclusive Client / Server if set to 1 or allows P2P (peer-to-peer) i.e. communication between clients if set to 0.

To go a bit deeper in the analysis or P2P impact, here is a graph to explain the P2P impact on the bandwidth.

Falcon BMS 4.33 Bandwidth usage with P2P

Falcon BMS 4.33 Bandwidth usage with P2P

As you can see, with P2P active, a client will use an average of 50Kbit/s for each P2P client connected to him… So make sure you have enough bandwidth to sustain all of that…


Configuring your MP session

On server side

Should have at least 1024Kbit/s per client connected. So if 20 clients: 20 x 1024 = 20480 Kbit/s…

Make sure you don’t use more than 70% of your line capacity or the side effects with line saturation might become a show stopper.

You will also need to make sure that all the clients will respect the following settings for clients (see below).


On client side

If you are on ADSL (upload less than 5 Mb/s in UPLOAD)

Add the following line to the Falcon BMS.cfg (Multiplayer section):

set g_bClientServerConnection 1 // Force CS connection
At the time of connection you will need to set a bandwidth of 1024 (even if your bandwidth is lower – beware of lag and side effects though).


If you are on cable or fiber (upload greater than 5Mb/s in UPLOAD)

Add the following line to the Falcon BMS.cfg (Multiplayer section):

set g_bClientServerConnection 0 // Force CS connection, in this case, 0 allows P2P connectivity
Set the upload to 4096 Kbit/s (higher is not really useful).



There are some simple rules to apply to at least make sure connectivity experience is best. There will be some other articles on tools that help you on connectivity…

Meanwhile, the last tip I could give you is make sure your TE is not too heavy in troops movements since load on CPU will be high as well as network traffic activity…

This does not guaranty a 100% success rate but with those rules and high player load, you should be pretty safe! 🙂


Enjoy your falcon flights!