slackhq/nebula · error

entry %v.route in tun.unsafe_routes failed to parse: %v

Error message

entry %v.route in tun.unsafe_routes failed to parse: %v

What it means

Config validation error in parseUnsafeRoutes: the i+1-th entry's `route` value, rendered with %v, was rejected by netip.ParsePrefix — not a valid CIDR (missing /len, host bits set, malformed). The ParsePrefix error is included.

Source

Thrown at overlay/route.go:292

		install := true
		rInstall, ok := m["install"]
		if ok {
			install, err = strconv.ParseBool(fmt.Sprintf("%v", rInstall))
			if err != nil {
				return nil, fmt.Errorf("entry %v.install in tun.unsafe_routes is not a boolean: %v", i+1, err)
			}
		}

		r := Route{
			Via:     gateways,
			MTU:     mtu,
			Metric:  metric,
			Install: install,
		}

		r.Cidr, err = netip.ParsePrefix(fmt.Sprintf("%v", rRoute))
		if err != nil {
			return nil, fmt.Errorf("entry %v.route in tun.unsafe_routes failed to parse: %v", i+1, err)
		}

		for _, network := range networks {
			if network.Contains(r.Cidr.Addr()) {
				return nil, fmt.Errorf(
					"entry %v.route in tun.unsafe_routes is contained within the configured vpn networks; route: %v, network: %v",
					i+1,
					r.Cidr.String(),
					network.String(),
				)
			}
		}

		routes[i] = r
	}

	return routes, nil
}

View on GitHub (pinned to dd8f660c0a)

Solutions

1. Write route as a proper network prefix like 10.1.0.0/16
2. Ensure the length suffix is present and in range

When it happens

Trigger: Thrown at overlay/route.go:292 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of slackhq/nebula@dd8f660c0a (2026-09-03). Data as JSON: /api/errors/0c4b2b5674741b58. Report an issue: GitHub.