slackhq/nebula · error

entry .gateway in tun.unsafe_routes

Error message

entry .gateway in tun.unsafe_routes[%v].via[%v] is not present

What it means

Configuration validation error in parseUnsafeRoutes for the multi-gateway form of tun.unsafe_routes. When a route's 'via' is a list of gateway maps, each map must contain a 'gateway' key; this fires when one of those maps omits it, meaning the gateway address for that multipath route entry is unspecified and no route can be built for it.

Solutions

1. Add gateway: <IP> to each via list element

When it happens

Trigger: Thrown at overlay/route.go:231 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of slackhq/nebula@dd8f660c0a (2026-09-03). Data as JSON: /api/errors/40ddb69e0e3a99ef. Report an issue: GitHub.

Appendix: source

Thrown at overlay/route.go:231

		case string:
			viaIp, err := netip.ParseAddr(via)
			if err != nil {
				return nil, fmt.Errorf("entry %v.via in tun.unsafe_routes failed to parse address: %v", i+1, err)
			}

			gateways = routing.Gateways{routing.NewGateway(viaIp, 1)}

		case []any:
			gateways = make(routing.Gateways, len(via))
			for ig, v := range via {
				gatewayMap, ok := v.(map[string]any)
				if !ok {
					return nil, fmt.Errorf("entry %v in tun.unsafe_routes[%v].via is invalid", i+1, ig+1)
				}

				rGateway, ok := gatewayMap["gateway"]
				if !ok {
					return nil, fmt.Errorf("entry .gateway in tun.unsafe_routes[%v].via[%v] is not present", i+1, ig+1)
				}

				parsedGateway, ok := rGateway.(string)
				if !ok {
					return nil, fmt.Errorf("entry .gateway in tun.unsafe_routes[%v].via[%v] is not a string", i+1, ig+1)
				}

				gatewayIp, err := netip.ParseAddr(parsedGateway)
				if err != nil {
					return nil, fmt.Errorf("entry .gateway in tun.unsafe_routes[%v].via[%v] failed to parse address: %v", i+1, ig+1, err)
				}

				rGatewayWeight, ok := gatewayMap["weight"]
				if !ok {
					rGatewayWeight = 1
				}

				gatewayWeight, ok := rGatewayWeight.(int)

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