netbirdio/netbird · error

add output DNAT rule: %w

Error message

add output DNAT rule: %w

What it means

Error "add output DNAT rule: %w" thrown in netbirdio/netbird.

Source

Thrown at client/firewall/iptables/router_linux.go:1094

	if _, exists := r.rules[ruleID]; exists {
		return nil
	}

	if err := r.ensureNATOutputChain(); err != nil {
		return err
	}

	dnatRule := []string{
		"-p", strings.ToLower(protoForFamily(protocol, localAddr.Is6())),
		"--dport", strconv.Itoa(int(originalPort)),
		"-d", localAddr.String(),
		"-j", "DNAT",
		"--to-destination", ":" + strconv.Itoa(int(translatedPort)),
	}

	if err := r.iptablesClient.Append(tableNat, chainNATOutput, dnatRule...); err != nil {
		return fmt.Errorf("add output DNAT rule: %w", err)
	}
	r.rules[ruleID] = dnatRule

	r.updateState()
	return nil
}

// RemoveOutputDNAT removes an OUTPUT chain DNAT rule.
func (r *router) RemoveOutputDNAT(localAddr netip.Addr, protocol firewall.Protocol, originalPort, translatedPort uint16) error {
	ruleID := fmt.Sprintf("output-dnat-%s-%s-%d-%d", localAddr.String(), protocol, originalPort, translatedPort)

	if dnatRule, exists := r.rules[ruleID]; exists {
		if err := r.iptablesClient.Delete(tableNat, chainNATOutput, dnatRule...); err != nil {
			return fmt.Errorf("delete output DNAT rule: %w", err)
		}
		delete(r.rules, ruleID)
	}

View on GitHub (pinned to 93e97f4bf1)

When it happens

Trigger: Thrown at client/firewall/iptables/router_linux.go:1094 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of netbirdio/netbird@93e97f4bf1 (2026-08-16). Data as JSON: /api/errors/0fb28331993fa4d9. Report an issue: GitHub.