Scanning Isolated Networks from One Host

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This guide walks through running multiple daemon instances on a single host, each scanning different interfaces or network segments. For help deciding whether this is the right approach for your network, see Planning Daemon Deployment.

How multiple daemons coexist

Each scanopy-daemon install on a host takes its own slot — an independent install with its own config file, service, and log file. The first install takes the default slot (scanopy-daemon); each additional install takes the next number (scanopy-daemon-2, scanopy-daemon-3, …). The installer allocates the slot for you — you don't name it.

Each slot's config holds its own daemon ID, API key, server URL, and runtime state. Slots are fully independent — starting, stopping, or reconfiguring one does not affect the others. A slot is not the daemon's name: the name is assigned by the server and shown in the app, and can be changed there without moving the slot.

Restricting daemons to specific interfaces

Use --interfaces to limit which network interfaces a daemon scans. Without it, the daemon scans all interfaces. Names are the host's own interface names.

# Scan only eth0
sudo scanopy-daemon install --interfaces eth0

# Scan two interfaces
sudo scanopy-daemon install --interfaces eth0,eth1

The same setting works in the config file:

{ "interfaces": ["eth0", "eth1"] }

When an interface restriction is set, the daemon only reports and scans subnets attached to those interfaces. This prevents overlap between daemon instances sharing the same host.

Ports and bind addresses

Every daemon instance runs an HTTP server, bound to 0.0.0.0:60073 by default. Because 0.0.0.0 binds all interfaces, the first daemon claims port 60073 on every address — a second daemon can't reuse it.

The installer handles this. Install another daemon without asking for a specific port and it takes the next free one — 60074, 60075, and so on.

Set --daemon-port only when you need a specific port. A ServerPoll daemon is the case that matters: its port is the one the server dials, so the install command already carries it and the installer leaves it alone.

To pin a daemon's listener to one interface, give it that interface's IP with --bind-address:

sudo scanopy-daemon install --interfaces <interface> --bind-address 192.168.1.10

The same settings work in the config file:

{ "bind_address": "192.168.1.10", "daemon_port": 60073 }

Setting up multiple daemons

Create a separate daemon entry in Discover > Daemons for each instance. Each is provisioned with its own API key and can target the same or different sites. During setup, use the Advanced tab to set that instance's interface restrictions, bind address, and port under Network Discovery — they're baked into the install artifact the wizard gives you, so you don't have to add them by hand.

Run each daemon's own install artifact on the host. Each run takes a fresh slot, so you can install several without them overwriting each other — no per-instance flags to remember.

Each install registers a per-slot background service that starts immediately and on every reboot, and writes that slot's config. Interface, bind address, and port are persisted in each slot's config, so restarting or re-running install doesn't need them again.

To restart one slot:

sudo scanopy-daemon restart --instance scanopy-daemon-2

Daemons before 0.18.0 have no restart, so restart the slot's service instead. scanopy-daemon list shows each slot's exact service id:

sudo systemctl restart scanopy-daemon-2

systemd template (manual)

Scanopy provides a systemd template unit for running multiple instances. Download and install it:

sudo curl -o /etc/systemd/system/[email protected] \
  https://raw.githubusercontent.com/scanopy/scanopy/main/scanopy-daemon%40.service
sudo systemctl daemon-reload

The template uses the instance identifier as --interfaces. Each instance needs its own bind address and port — set these via environment overrides:

ExecStart=/usr/local/bin/scanopy-daemon --interfaces=%i
SyslogIdentifier=scanopy-daemon-%i

To configure the bind address and port per instance, create a systemd override:

sudo systemctl edit scanopy-daemon@eth0

[Service]
Environment="SCANOPY_BIND_ADDRESS=192.168.1.10"
Environment="SCANOPY_DAEMON_PORT=60073"

sudo systemctl edit scanopy-daemon@eth1

[Service]
Environment="SCANOPY_BIND_ADDRESS=10.0.0.10"
Environment="SCANOPY_DAEMON_PORT=60074"

Enable and start instances by appending the interface name after @:

sudo systemctl enable --now scanopy-daemon@eth0
sudo systemctl enable --now scanopy-daemon@eth1

Each instance gets separate journal logs:

journalctl -u scanopy-daemon@eth0
journalctl -u scanopy-daemon@eth1

Listing installed daemons

To see which daemons are installed on a host — their slots, services, config paths, and IDs — run:

scanopy-daemon list

Each line is one installed slot. Use any of the values it prints as the --instance selector for install and restart, or the --name selector for uninstall.

Upgrading

All daemon slots share the same binary. Each daemon's Update button in the app gives the commands to download the latest binary and restart that daemon's slot. Configuration is preserved across upgrades — each slot reads its settings from its own config file on startup.

For legacy systemd-template instances (scanopy-daemon@<name>), stop them, replace the binary, then start them:

sudo systemctl stop scanopy-daemon@eth0 scanopy-daemon@eth1
sudo systemctl start scanopy-daemon@eth0 scanopy-daemon@eth1