Documents You Did Not Print

If documents appear that you did not send - junk text, fragments of someone else's receipt, or the output of a port scanner - your printer port has been found by someone else.

That is not a break-in. Every printer port is reachable from the whole internet, by design: it is what lets a POS terminal or a CI runner anywhere print to it. Ports in the 9100 block are also scanned constantly, because that is where network printers live.

The fix: the IP whitelist

Open Workspace Settings -> IP Whitelist, switch it on, and list the addresses allowed to print:

• one entry per line, exact IP or CIDR range (203.0.113.7, 203.0.113.0/24);
• # starts a comment, so you can label which entry is which;
• connections from anywhere else are reset the moment they open.

New workspaces start with this already enabled, holding the IP you created the workspace from. If strangers are printing into yours, the whitelist has been turned off or widened at some point.

Workspace Settings -> Access Log shows what has been connecting lately, allowed and rejected alike - useful for confirming the whitelist now does what you expect.

What this does not protect

The whitelist controls who may connect. It does not encrypt anything: raw TCP is unencrypted by definition, so whatever you print travels in the clear either way. Keep real customer data out of the hosted service - see Security guidelines and Choosing a test printer.

Still stuck?

Email support@virtual-printer.online with the printer's protocol and port, what your application sent, and what you expected to see.