NAPS2 - Scanner Sharing

Scanner Sharing

NAPS2 allows you to use scanners connected to one computer from any other computer on the local network. Scanners can be shared across Windows, Mac, and Linux using the ESCL driver.

Server

On the computer the scanner is connected to, you can open the "Scanner Sharing" window from the "Profiles" window (or the "Scan" dropdown).

Click the "Share" button.

Select the scanning device that you want to share. You can also change the name that other computers will see.

You can share as many devices as you like. They will be available as long as NAPS2 is running.

Client

On the computer you want to scan from, create a NAPS2 profile with the "ESCL Driver" selected and choose the shared scanner.

Then you can scan!

Advanced

Other Clients

Scanner sharing uses the standard ESCL protocol, which means it works with any ESCL-compatible client, including on Android or iPhone. Some examples:

Other Servers

If the server is running Linux, you don't need to use NAPS2 if you don't want to:

Or, if the client is using Windows and the server is using Linux, you can use SANE over the network if you install SANEWinDS (v1.2+) on Windows. This doesn't use ESCL - instead, SANEWinDS provides a TWAIN device on the client that will connect to the SANE server.

Running as a Service

Scanner sharing currently only works while NAPS2 is running on the server. Running as a service is planned but not currently supported.

Network Traffic

ESCL uses mDNS for service discovery, which involves both the client and server sending multicast packets to UDP 224.0.0.251:5353 (which get delivered to everything on the network).

If you have a network firewall, you'll need to make sure it allows both the mDNS packets and direct IP to IP connections between the client and server.

IP Changes

NAPS2 always checks mDNS when scanning, meaning that connections should still work even if the server IP changes.

Subnet Boundaries

If your client and server are on different subnets, mDNS packets usually aren't transferred across subnet boundaries so scanner sharing won't work by default. There are some solutions:

HTTPS

By default, scanner sharing uses HTTPS with an auto-generated self-signed certificate, but may fall back to HTTP if there's a problem. Admins can force HTTPS to always be used or provide a custom certificate.

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