feat: support for relay dns

README.md

@@ -91,19 +91,30 @@ chmod +x nanodns-darwin-arm64
 | Variable | Description | Default | Example |
 |----------|-------------|---------|---------|
 | DNS_PORT | UDP port for DNS server | 53 | 5353 |
+| DNS_RELAY_SERVERS | Comma-separated upstream DNS servers | - | 8.8.8.8:53,1.1.1.1:53 |
 | A_xxx | A Record Details | - | - |
 | CNAME_xxx | CNAME Record Details | - | - |
 | MX_xxx | MX Record Details | - | - |
 | TXT_xxx | TXT Record Details | - | - |
 
+### DNS Resolution Strategy
+
+NanoDNS follows this resolution order:
+
+1. Check configured local records first
+2. If no local record found and relay is enabled, forward to upstream DNS servers
+3. Return first successful response from relay servers
+
 ### Record Format
 
 All records use the `|` character as a separator. The general format is:
-```
+
+```txt
 RECORD_TYPE_NUMBER=domain|value[|ttl]
 ```
 
 ### A Records
+
 ```
 A_REC1=domain|ip|ttl
 A_REC2=domain|service:servicename|ttl
@@ -115,6 +126,7 @@ A_REC2=api.example.com|service:webapp
 ```
 
 ### CNAME Records
+
 ```
 CNAME_REC1=domain|target|ttl
 ```
@@ -124,6 +136,7 @@ CNAME_REC1=www.example.com|app.example.com|3600
 ```
 
 ### MX Records
+
 ```
 MX_REC1=domain|priority|mailserver|ttl
 ```
@@ -134,6 +147,7 @@ MX_REC2=example.com|20|mail2.example.com
 ```
 
 ### TXT Records
+
 ```
 TXT_REC1=domain|"text value"|ttl
 ```
@@ -143,36 +157,40 @@ TXT_REC1=example.com|v=spf1 include:_spf.example.com ~all|3600
 TXT_REC2=_dmarc.example.com|v=DMARC1; p=reject; rua=mailto:dmarc@example.com
 ```
 
-
 ## Docker Usage
 
 ### Using Docker Run
+
 ```bash
 docker run -d \
   --name nanodns \
   -p 5353:5353/udp \
   -e DNS_PORT=5353 \
+  -e DNS_RELAY_SERVERS=8.8.8.8:53,1.1.1.1:53 \  # Optional relay configuration
   -e "A_REC1=app.example.com|192.168.1.10|300" \
   -e "A_REC2=api.example.com|service:webapp" \
   -e "TXT_REC1=example.com|v=spf1 include:_spf.example.com ~all" \
   ghcr.io/mguptahub/nanodns:latest
 ```
 
 ### Using Docker Compose
+
 ```yaml
 name: nanodns
 services:
   dns:
     image: ghcr.io/mguptahub/nanodns:latest
     environment:
+      # DNS Server Configuration
       - DNS_PORT=5353  # Optional, defaults to 53
-      # A Records
+      - DNS_RELAY_SERVERS=8.8.8.8:53,1.1.1.1:53  # Optional relay servers
+
+      # Local Records
       - A_REC1=app.example.com|service:webapp
       - A_REC2=api.example.com|192.168.1.10|300
-      # TXT Records
       - TXT_REC1=example.com|v=spf1 include:_spf.example.com ~all
     ports:
-      - "${DNS_PORT:-5353}:${DNS_PORT:-5353}/udp"  # Uses DNS_PORT if set, otherwise 5353
+      - "${DNS_PORT:-5353}:${DNS_PORT:-5353}/udp"
     networks:
       - app_network
 
@@ -182,13 +200,15 @@ networks:
 ```
 
 ### Kubernetes
+
 For detailed instructions on deploying NanoDNS in Kubernetes, see our [Kubernetes Deployment Guide](kubernetes/README.md).
 
 ## Running Without Docker Compose
 
 ```bash
 # Set environment variables
 export DNS_PORT=5353
+export DNS_RELAY_SERVERS=8.8.8.8:53,1.1.1.1:53
 export A_REC1=app.example.com|192.168.1.10
 export TXT_REC1=example.com|v=spf1 include:_spf.example.com ~all
 
@@ -199,16 +219,15 @@ export TXT_REC1=example.com|v=spf1 include:_spf.example.com ~all
 ## Testing Records
 
 ```bash
-# Test using custom port
+# Test local records
 dig @localhost -p 5353 app.example.com A
 
-# Test CNAME record
-dig @localhost -p 5353 www.example.com CNAME
+# Test relay resolution (for non-local domains)
+dig @localhost -p 5353 google.com A
 
-# Test MX record
+# Test other record types
+dig @localhost -p 5353 www.example.com CNAME
 dig @localhost -p 5353 example.com MX
-
-# Test TXT record
 dig @localhost -p 5353 example.com TXT
 ```
 
@@ -222,6 +241,12 @@ dig @localhost -p 5353 example.com TXT
    - Use a port number above 1024 to avoid requiring root privileges
    - Set `DNS_PORT=5353` or another high-numbered port
 
+3. DNS Relay Issues:
+   - Verify upstream DNS servers are accessible
+   - Check network connectivity to relay servers
+   - Ensure correct format in DNS_RELAY_SERVERS (comma-separated, with ports)
+   - Monitor logs for relay errors
+
 ## Issues and Support
 
 ### Opening New Issues
@@ -237,7 +262,14 @@ Before opening a new issue:
    - Expected vs actual behavior
    - Error messages if any
 
-### Join as a Contributor
+## Community
+
+- Star the repository to show support
+- Watch for updates and new releases
+- Join discussions in issues and PRs
+- Share your use cases and feedback
+
+## Join as a Contributor
 
 We welcome contributions! Here's how to get started:
 
@@ -249,21 +281,6 @@ We welcome contributions! Here's how to get started:
    - PR process
    - Release workflow
 
-### Community
-
-- Star the repository to show support
-- Watch for updates and new releases
-- Join discussions in issues and PRs
-- Share your use cases and feedback
-
-## Contributing
-
-Please see [CONTRIBUTING.md](CONTRIBUTING.md) for:
-- Development setup
-- How to create PRs
-- Code style guidelines
-- Release process
-
 
 ## License and Usage Terms
 

cmd/server/main.go

@@ -12,8 +12,14 @@ func main() {
 	// Load records from environment variables
 	records := dns.LoadRecords()
 
+	// Get relay configuration
+	relayConfig := config.GetRelayConfig()
+	if relayConfig.Enabled {
+		log.Printf("DNS relay enabled, using nameservers: %v", relayConfig.Nameservers)
+	}
+
 	// Create DNS handler
-	handler := dns.NewHandler(records)
+	handler, _ := dns.NewHandler(records, relayConfig) // Fixed: Pass RelayConfig directly
 	externaldns.HandleFunc(".", handler.ServeDNS)
 
 	// Configure server

docs/docker.md

@@ -6,6 +6,7 @@ docker run -d \
   --name nanodns \
   -p 5353:5353/udp \
   -e DNS_PORT=5353 \
+  -e DNS_RELAY_SERVERS=8.8.8.8:53,1.1.1.1:53 \
   -e "A_REC1=app.example.com|192.168.1.10|300" \
   -e "TXT_REC1=example.com|v=spf1 include:_spf.example.com ~all" \
   ghcr.io/mguptahub/nanodns:latest
@@ -20,6 +21,7 @@ services:
     image: ghcr.io/mguptahub/nanodns:latest
     environment:
       - DNS_PORT=5353  # Optional, defaults to 53
+      - DNS_RELAY_SERVERS=8.8.8.8:53,1.1.1.1:53
       # A Records
       - A_REC1=app.example.com|service:webapp
       - A_REC2=api.example.com|192.168.1.10|300

docs/index.html

@@ -388,18 +388,17 @@ <h2 id="features">Features</h2>
             <div class="feature-card">
                 <div class="feature-icon"><i class="fas fa-cogs"></i></div>
                 <h3>Easy Configuration</h3>
-                <p>Configure DNS records using simple environment variables. Supports A, CNAME, MX, and TXT records.</p>
+                <p>Configure DNS records using simple environment variables. Supports A, CNAME, MX, and TXT records with optional relay DNS.</p>
             </div>
             <div class="feature-card">
-                <div class="feature-icon"><i class="fab fa-docker"></i></div>
-                <h3>Docker Integration</h3>
-                <p>Seamless integration with Docker and Kubernetes environments. Automatic service discovery and
-                    resolution.</p>
+                <div class="feature-icon"><i class="fas fa-route"></i></div>
+                <h3>Relay DNS</h3>
+                <p>Forward unmatched queries to upstream DNS servers. Support for multiple fallback servers with automatic failover.</p>
             </div>
             <div class="feature-card">
-                <div class="feature-icon"><i class="fas fa-tachometer-alt"></i></div>
-                <h3>Lightweight</h3>
-                <p>Minimal resource footprint. Perfect for development and production environments.</p>
+                <div class="feature-icon"><i class="fab fa-docker"></i></div>
+                <h3>Docker Integration</h3>
+                <p>Seamless integration with Docker and Kubernetes environments. Automatic service discovery and resolution.</p>
             </div>
         </section>
 

docs/kubernetes.md

@@ -9,6 +9,7 @@ metadata:
 data:
   # DNS Server Configuration
   DNS_PORT: "53"
+  DNS_RELAY_SERVERS: 8.8.8.8:53,1.1.1.1:53
 
   # A Records
   A_REC1: "app.example.com|service:frontend.default.svc.cluster.local"

internal/dns/handler.go

@@ -1,21 +1,35 @@
 package dns
 
 import (
+	"fmt"
 	"log"
 	"net"
 	"strings"
 
+	"github.com/mguptahub/nanodns/pkg/config"
 	"github.com/miekg/dns"
 )
 
 type Handler struct {
 	records map[string][]DNSRecord
+	relay   *RelayClient
 }
 
-func NewHandler(records map[string][]DNSRecord) *Handler {
+func NewHandler(records map[string][]DNSRecord, relayConfig config.RelayConfig) (*Handler, error) {
+	var relay *RelayClient
+	if relayConfig.Enabled {
+		// relay, _ = NewRelayClient(relayConfig)
+		var err error
+		relay, err = NewRelayClient(relayConfig)
+		if err != nil {
+			return nil, fmt.Errorf("failed to initialize relay client: %w", err)
+		}
+	}
+
 	return &Handler{
 		records: records,
-	}
+		relay:   relay,
+	}, nil
 }
 
 func (h *Handler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
@@ -26,13 +40,47 @@ func (h *Handler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	for _, q := range r.Question {
 		log.Printf("Query for %s (type: %v)", q.Name, dns.TypeToString[q.Qtype])
 
+		// Try local records first
 		if recs, exists := h.records[q.Name]; exists {
 			for _, rec := range recs {
 				if answer := h.createAnswer(q, rec); answer != nil {
 					m.Answer = append(m.Answer, answer)
 				}
 			}
 		}
+
+		// If no local records found and relay is enabled, try relay
+		if len(m.Answer) == 0 && h.relay != nil {
+			log.Printf("No local records found for %s, attempting relay", q.Name)
+
+			// Create a new message for just this question
+			relayReq := new(dns.Msg)
+			relayReq.SetQuestion(q.Name, q.Qtype)
+			relayReq.RecursionDesired = true
+
+			relayResp, err := h.relay.Relay(relayReq)
+			if err != nil {
+				log.Printf("Relay failed: %v", err)
+				// Continue with next question without breaking the loop
+				break
+			}
+
+			// Validate relay response
+			if relayResp.Rcode != dns.RcodeSuccess {
+				log.Printf("Relay returned non-success code: %v", dns.RcodeToString[relayResp.Rcode])
+				continue
+			}
+
+			// Add answers from relay response
+			m.Answer = append(m.Answer, relayResp.Answer...)
+			m.Ns = append(m.Ns, relayResp.Ns...)
+			m.Extra = append(m.Extra, relayResp.Extra...)
+
+			// If we got answers from relay, we're not authoritative
+			if len(relayResp.Answer) > 0 {
+				m.Authoritative = false
+			}
+		}
 	}
 
 	w.WriteMsg(m)