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Connecting printers

Relay client on a NAS or server (Docker)

Run the relay client as a container on Synology, QNAP, Unraid or any server with Docker.

On a NAS or a server that runs around the clock, the relay client works as a Docker container. It addresses the printers on your network directly over IPP, so they do not have to be installed anywhere. Like the desktop version, it only connects outbound and needs no open ports.

Prerequisites

  • A NAS or server with Docker (Synology Container Manager, QNAP Container Station, Unraid, or Docker on Linux).
  • Network printers that speak IPP, with their addresses, for example ipp://192.168.1.20/ipp/print. Most network printers sold in the last ten years do. The address is usually shown in the printer's web interface or network settings.
  • A Sealed Print account. Any member can connect a relay client, on every plan.

One-time setup

1. Start the container

Start the container with the address of this server and a list of your printers. The download page shows the command with the right address:

docker run -d --name sealedprint-relay --restart unless-stopped -v sealedprint-relay:/data \
  -e SEALEDPRINT_CLOUD_URL=https://www.sealedprint.com \
  -e SEALEDPRINT_PRINTERS="Office=ipp://192.168.1.20/ipp/print" ghcr.io/nova-digital-group/sealedprint-relay:latest
  • SEALEDPRINT_PRINTERS lists the printers as Name=address, separated by commas, for example Office=ipp://192.168.1.20/ipp/print,Label=ipps://label.local/ipp/print. The name is how the printer appears in Sealed Print.
  • The volume sealedprint-relay keeps the connection. Without it, you would have to connect again after every update of the container.

On a NAS with a graphical container manager, enter the same image, the two environment variables and a volume mounted at /data, and set the restart policy to "unless stopped".

2. Confirm the code

While it is not connected, the container log shows a code and a link:

docker logs sealedprint-relay

Open the link, sign in and check that the code matches, then select Connect.

3. Share printers

In the web app, go to Destinations → Relay clients and switch on Shared for the printers that should become destinations. Share them with all members in the Access column if others should print to them too.

Every time

Nothing to do. The container keeps the connection and prints jobs as they arrive. To update, pull the new image version and start the container again with the same volume:

docker pull ghcr.io/nova-digital-group/sealedprint-relay:latest

Troubleshooting

  • No code in the log: the container may already be connected. Check Relay clients in the web app.
  • A printer is missing or jobs do not arrive at it: the container cannot reach the printer address. Check the address in SEALEDPRINT_PRINTERS and that the NAS can reach the printer on the network, then start the container again.
  • Jobs fail at the printer: open the job in the queue; the delivery shows the printer's own message. Check that the printer supports PDF over IPP (IPP Everywhere).
  • Connect a further organization: run docker exec -it sealedprint-relay node /app/sealedprint-relay.cjs pair and confirm the code in the other organization.

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