# Update UDP Port for the voxl-mavlink-server

Source: https://forum.modalai.com/topic/4669/update-udp-port-for-the-voxl-mavlink-server
Category: VOXL SDK and Software (https://forum.modalai.com/category/47/voxl-sdk-and-software)
Tags: voxl-sdk
Posted: 2025-08-12 07:44:21 UTC by ashwin
Replies: 9 · Views: 5746

## ashwin · 2025-08-12 07:44:21 UTC

Re: [voxl-mavlink-server GCS udp port](/topic/3959/voxl-mavlink-server-gcs-udp-port)

I’m currently working on a solution to connect a fleet of drones simultaneously to our home-grown Ground Control Station (GCS). Until now, we’ve been differentiating drones using unique IP and port combinations. However, this approach is not feasible with VOXL, as it transmits data to a fixed GCS IP and a hard-coded port via voxl-mavlink-server.

I came across a related topic where modifying the port was discussed. I’d like to know if there’s a supported method to configure or override the default port settings in voxl-mavlink-server, so we can enable multiple drone connections without conflict.

Any guidance or suggestions on this would be greatly appreciated.

## Reply by Eric Katzfey (ModalAI staff) · 2025-08-13 15:01:10 UTC

@ashwin Can you differentiate each drone based on the drone's IP address? Those will be unique.

## Reply by ashwin · 2025-08-22 06:44:33 UTC (in reply to Eric Katzfey)

@Eric-Katzfey Hi Eric thank you for the reply, we didn't exactly try using because of the mavlinks limitation in the working and handling of UDP connection as it sends data to localhost Port 14550 so all of the drones would be sending their data to 127.0.0.1 14550 port and this would create problem for handling multiple drone with same port.

## Reply by Eric Katzfey (ModalAI staff) · 2025-08-22 15:45:17 UTC (in reply to ashwin)

@ashwin I'm not really understanding the issue. Mavlink has no limitation to send packets to a localhost address. On VOXL 2 we configure voxl-px4 to send to localhost but that is because voxl-mavlink-server is the application that actually sends the data to the GCS. At the GCS you will see each connection with a unique IP address.

## Reply by brandon · 2025-10-22 19:30:42 UTC (in reply to Eric Katzfey)

@Eric-Katzfey I have this issue as well. The voxl-mavlink-server only replies to 14550 even when GCS initiates connection. This prevents multiple drones from communicating to separate processes on a common computer. Please see my response here where I tried to outline the issue: https://forum.modalai.com/post/24187

If this command worked all of the posts relating to the port issue would be resolved:  mavproxy.py --master=udpout:<voxl_ip>:14550

## Reply by Zachary Lowell 0 · 2025-10-24 15:07:56 UTC

@all - you can just change the SYS_ID of each drone and this should solve the port confliction.

## Reply by Eric Katzfey (ModalAI staff) · 2025-11-04 16:23:33 UTC (in reply to brandon)

@brandon The latest voxl-mavlink-server is available here: http://voxl-packages.modalai.com/dists/qrb5165/dev/binary-arm64/voxl-mavlink-server_1.4.12-202511040816_arm64.deb. This has added configuration for the GCS ports and also fixes the above issue so that it now responds to the correct port.

## Reply by brandon · 2025-12-11 18:59:39 UTC (in reply to Eric Katzfey)

@Eric-Katzfey This works! Thank you!

## Reply by brandon · 2026-01-31 00:54:02 UTC (in reply to Eric Katzfey)

@Eric-Katzfey Is this fix in the new 1.5.0 binary? We received a new Starling 2 Max but I think I had to downgrade to this binary to get connectivity.

## Reply by Eric Katzfey (ModalAI staff) · 2026-01-31 02:18:06 UTC (in reply to brandon)

@brandon You'll need to load SDK v1.6.x to get it.