abiosoft/colima · error

the last octet of gateway

Error message

the last octet of gateway %q is not 2

What it means

validateGatewayAddress enforces Lima's addressing convention: after confirming the gateway is IPv4, the fourth octet (ip4[3]) must be exactly 2. Lima reserves .1 for the host-side interface and .2 for the gateway inside the virtual network, so any other final octet is rejected with the address echoed.

Solutions

  1. Change the last octet to 2, e.g. 192.168.104.2, within a subnet that does not collide with the LAN
  2. Pick a different /24 subnet if .2 is already spoken for
  3. Omit gatewayAddress to keep default network settings

Example fix

# before
network:
  gatewayAddress: 192.168.104.1

# after
network:
  gatewayAddress: 192.168.104.2
Defensive patterns

Strategy: validation

Validate before calling

if ip4 := c.Network.GatewayAddress.To4(); ip4 != nil && ip4[3] != 2 {
    // adjust the last octet to 2 before running ValidateConfig
}

Try / catch

if err := configmanager.ValidateConfig(c); err != nil {
    if strings.Contains(err.Error(), "last octet") {
        // Lima reserves .2 for the gateway; change e.g. 192.168.104.1 to 192.168.104.2
    }
}

Prevention

When it happens

Trigger: gatewayAddress set to an IPv4 address ending in .1, .254, or any octet other than 2, such as 192.168.104.1 copied from a typical router gateway configuration.

Common situations: Reusing a home or office router address (conventionally .1) as the colima gateway; network plans where .2 is already assigned to another host; not realizing colima must own the .2 address in its subnet.

Related errors

AI-assisted analysis of abiosoft/colima@c3a5f9184d (2026-08-15). Data as JSON: /api/errors/d578cd425212ae6d. Report an issue: GitHub.

Appendix: source

Thrown at config/configmanager/configmanager.go:144

func Teardown() error {
	dir := config.CurrentProfile().ConfigDir()
	if _, err := os.Stat(dir); err == nil {
		return os.RemoveAll(dir)
	}
	return nil
}

// Validates that gateway is a valid IPv4 address and that the last octet is “2”.
// Lima uses the last octet as 2 for gateways.
func validateGatewayAddress(gateway net.IP) error {
	ip4 := gateway.To4()
	if ip4 == nil {
		return fmt.Errorf("gateway %q is not IPv4", gateway)
	}

	// Check last octet
	if ip4[3] != 2 {
		return fmt.Errorf("the last octet of gateway %q is not 2", gateway)
	}

	return nil
}

// validateMounts ensures mount paths do not contain spaces, which are not
// supported by the underlying Lima runtime and otherwise fail silently.
// See https://github.com/abiosoft/colima/issues/1471.
func validateMounts(mounts []config.Mount) error {
	for _, m := range mounts {
		for _, p := range []string{m.Location, m.MountPoint} {
			if strings.Contains(p, " ") {
				return fmt.Errorf("mount path with spaces is not supported by the underlying Lima runtime: %q", p)
			}
		}
	}
	return nil
}

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