diff --git a/api/v1alpha1/tls_types.go b/api/v1alpha1/tls_types.go
index b926558c525..bf2a1f50569 100644
--- a/api/v1alpha1/tls_types.go
+++ b/api/v1alpha1/tls_types.go
@@ -69,7 +69,12 @@ type TLSSettings struct {
 	SignatureAlgorithms []string `json:"signatureAlgorithms,omitempty"`
 
 	// ALPNProtocols supplies the list of ALPN protocols that should be
-	// exposed by the listener. By default h2 and http/1.1 are enabled.
+	// exposed by the listener or used by the proxy to connect to the backend.
+	// Defaults:
+	// 1. HTTPS Routes: h2 and http/1.1 are enabled in listener context.
+	// 2. Other Routes: ALPN is disabled.
+	// 3. Backends: proxy uses the appropriate ALPN options for the backend protocol.
+	// When an empty list is provided, the ALPN TLS extension is disabled.
 	// Supported values are:
 	// - http/1.0
 	// - http/1.1
diff --git a/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_clienttrafficpolicies.yaml b/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_clienttrafficpolicies.yaml
index ad17b8101d2..d3afb65b302 100644
--- a/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_clienttrafficpolicies.yaml
+++ b/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_clienttrafficpolicies.yaml
@@ -689,7 +689,12 @@ spec:
                   alpnProtocols:
                     description: |-
                       ALPNProtocols supplies the list of ALPN protocols that should be
-                      exposed by the listener. By default h2 and http/1.1 are enabled.
+                      exposed by the listener or used by the proxy to connect to the backend.
+                      Defaults:
+                      1. HTTPS Routes: h2 and http/1.1 are enabled in listener context.
+                      2. Other Routes: ALPN is disabled.
+                      3. Backends: proxy uses the appropriate ALPN options for the backend protocol.
+                      When an empty list is provided, the ALPN TLS extension is disabled.
                       Supported values are:
                       - http/1.0
                       - http/1.1
diff --git a/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_envoyproxies.yaml b/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_envoyproxies.yaml
index 4277092874a..84fb126a79b 100644
--- a/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_envoyproxies.yaml
+++ b/charts/gateway-helm/crds/generated/gateway.envoyproxy.io_envoyproxies.yaml
@@ -51,7 +51,12 @@ spec:
                   alpnProtocols:
                     description: |-
                       ALPNProtocols supplies the list of ALPN protocols that should be
-                      exposed by the listener. By default h2 and http/1.1 are enabled.
+                      exposed by the listener or used by the proxy to connect to the backend.
+                      Defaults:
+                      1. HTTPS Routes: h2 and http/1.1 are enabled in listener context.
+                      2. Other Routes: ALPN is disabled.
+                      3. Backends: proxy uses the appropriate ALPN options for the backend protocol.
+                      When an empty list is provided, the ALPN TLS extension is disabled.
                       Supported values are:
                       - http/1.0
                       - http/1.1
diff --git a/internal/gatewayapi/clienttrafficpolicy.go b/internal/gatewayapi/clienttrafficpolicy.go
index bded79d4cf9..1c8d0f8af4a 100644
--- a/internal/gatewayapi/clienttrafficpolicy.go
+++ b/internal/gatewayapi/clienttrafficpolicy.go
@@ -780,7 +780,7 @@ func (t *Translator) buildListenerTLSParameters(policy *egv1a1.ClientTrafficPoli
 		return irTLSConfig, nil
 	}
 
-	if len(tlsParams.ALPNProtocols) > 0 {
+	if tlsParams.ALPNProtocols != nil {
 		irTLSConfig.ALPNProtocols = make([]string, len(tlsParams.ALPNProtocols))
 		for i := range tlsParams.ALPNProtocols {
 			irTLSConfig.ALPNProtocols[i] = string(tlsParams.ALPNProtocols[i])
diff --git a/internal/gatewayapi/testdata/clienttrafficpolicy-tls-settings.in.yaml b/internal/gatewayapi/testdata/clienttrafficpolicy-tls-settings.in.yaml
index bc5878a52f0..ffe526627f2 100644
--- a/internal/gatewayapi/testdata/clienttrafficpolicy-tls-settings.in.yaml
+++ b/internal/gatewayapi/testdata/clienttrafficpolicy-tls-settings.in.yaml
@@ -26,6 +26,29 @@ clientTrafficPolicies:
         resumption:
           stateless: {}
           stateful: {}
+- apiVersion: gateway.envoyproxy.io/v1alpha1
+  kind: ClientTrafficPolicy
+  metadata:
+    namespace: envoy-gateway
+    name: target-gateway-2
+  spec:
+    targetRef:
+      group: gateway.networking.k8s.io
+      kind: Gateway
+      name: gateway-2
+    tls:
+      alpnProtocols: []
+- apiVersion: gateway.envoyproxy.io/v1alpha1
+  kind: ClientTrafficPolicy
+  metadata:
+    namespace: envoy-gateway
+    name: target-gateway-3
+  spec:
+    targetRef:
+      group: gateway.networking.k8s.io
+      kind: Gateway
+      name: gateway-3
+    tls:
 gateways:
 - apiVersion: gateway.networking.k8s.io/v1
   kind: Gateway
@@ -52,6 +75,44 @@ gateways:
       allowedRoutes:
         namespaces:
           from: Same
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: Gateway
+  metadata:
+    namespace: envoy-gateway
+    name: gateway-2
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - name: http-1
+      protocol: HTTPS
+      port: 443
+      allowedRoutes:
+        namespaces:
+          from: Same
+      tls:
+        mode: Terminate
+        certificateRefs:
+        - name: tls-secret-1
+          namespace: envoy-gateway
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: Gateway
+  metadata:
+    namespace: envoy-gateway
+    name: gateway-3
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - name: http-1
+      protocol: HTTPS
+      port: 443
+      allowedRoutes:
+        namespaces:
+          from: Same
+      tls:
+        mode: Terminate
+        certificateRefs:
+        - name: tls-secret-1
+          namespace: envoy-gateway
 secrets:
 - apiVersion: v1
   kind: Secret
diff --git a/internal/gatewayapi/testdata/clienttrafficpolicy-tls-settings.out.yaml b/internal/gatewayapi/testdata/clienttrafficpolicy-tls-settings.out.yaml
index ad3ed484f56..e673ed66b7a 100644
--- a/internal/gatewayapi/testdata/clienttrafficpolicy-tls-settings.out.yaml
+++ b/internal/gatewayapi/testdata/clienttrafficpolicy-tls-settings.out.yaml
@@ -41,6 +41,57 @@ clientTrafficPolicies:
         status: "True"
         type: Accepted
       controllerName: gateway.envoyproxy.io/gatewayclass-controller
+- apiVersion: gateway.envoyproxy.io/v1alpha1
+  kind: ClientTrafficPolicy
+  metadata:
+    creationTimestamp: null
+    name: target-gateway-2
+    namespace: envoy-gateway
+  spec:
+    targetRef:
+      group: gateway.networking.k8s.io
+      kind: Gateway
+      name: gateway-2
+    tls: {}
+  status:
+    ancestors:
+    - ancestorRef:
+        group: gateway.networking.k8s.io
+        kind: Gateway
+        name: gateway-2
+        namespace: envoy-gateway
+      conditions:
+      - lastTransitionTime: null
+        message: Policy has been accepted.
+        reason: Accepted
+        status: "True"
+        type: Accepted
+      controllerName: gateway.envoyproxy.io/gatewayclass-controller
+- apiVersion: gateway.envoyproxy.io/v1alpha1
+  kind: ClientTrafficPolicy
+  metadata:
+    creationTimestamp: null
+    name: target-gateway-3
+    namespace: envoy-gateway
+  spec:
+    targetRef:
+      group: gateway.networking.k8s.io
+      kind: Gateway
+      name: gateway-3
+  status:
+    ancestors:
+    - ancestorRef:
+        group: gateway.networking.k8s.io
+        kind: Gateway
+        name: gateway-3
+        namespace: envoy-gateway
+      conditions:
+      - lastTransitionTime: null
+        message: Policy has been accepted.
+        reason: Accepted
+        status: "True"
+        type: Accepted
+      controllerName: gateway.envoyproxy.io/gatewayclass-controller
 gateways:
 - apiVersion: gateway.networking.k8s.io/v1
   kind: Gateway
@@ -118,6 +169,100 @@ gateways:
         kind: HTTPRoute
       - group: gateway.networking.k8s.io
         kind: GRPCRoute
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: Gateway
+  metadata:
+    creationTimestamp: null
+    name: gateway-2
+    namespace: envoy-gateway
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      name: http-1
+      port: 443
+      protocol: HTTPS
+      tls:
+        certificateRefs:
+        - group: null
+          kind: null
+          name: tls-secret-1
+          namespace: envoy-gateway
+        mode: Terminate
+  status:
+    listeners:
+    - attachedRoutes: 0
+      conditions:
+      - lastTransitionTime: null
+        message: Sending translated listener configuration to the data plane
+        reason: Programmed
+        status: "True"
+        type: Programmed
+      - lastTransitionTime: null
+        message: Listener has been successfully translated
+        reason: Accepted
+        status: "True"
+        type: Accepted
+      - lastTransitionTime: null
+        message: Listener references have been resolved
+        reason: ResolvedRefs
+        status: "True"
+        type: ResolvedRefs
+      name: http-1
+      supportedKinds:
+      - group: gateway.networking.k8s.io
+        kind: HTTPRoute
+      - group: gateway.networking.k8s.io
+        kind: GRPCRoute
+- apiVersion: gateway.networking.k8s.io/v1
+  kind: Gateway
+  metadata:
+    creationTimestamp: null
+    name: gateway-3
+    namespace: envoy-gateway
+  spec:
+    gatewayClassName: envoy-gateway-class
+    listeners:
+    - allowedRoutes:
+        namespaces:
+          from: Same
+      name: http-1
+      port: 443
+      protocol: HTTPS
+      tls:
+        certificateRefs:
+        - group: null
+          kind: null
+          name: tls-secret-1
+          namespace: envoy-gateway
+        mode: Terminate
+  status:
+    listeners:
+    - attachedRoutes: 0
+      conditions:
+      - lastTransitionTime: null
+        message: Sending translated listener configuration to the data plane
+        reason: Programmed
+        status: "True"
+        type: Programmed
+      - lastTransitionTime: null
+        message: Listener has been successfully translated
+        reason: Accepted
+        status: "True"
+        type: Accepted
+      - lastTransitionTime: null
+        message: Listener references have been resolved
+        reason: ResolvedRefs
+        status: "True"
+        type: ResolvedRefs
+      name: http-1
+      supportedKinds:
+      - group: gateway.networking.k8s.io
+        kind: HTTPRoute
+      - group: gateway.networking.k8s.io
+        kind: GRPCRoute
 infraIR:
   envoy-gateway/gateway-1:
     proxy:
@@ -141,6 +286,36 @@ infraIR:
           gateway.envoyproxy.io/owning-gateway-name: gateway-1
           gateway.envoyproxy.io/owning-gateway-namespace: envoy-gateway
       name: envoy-gateway/gateway-1
+  envoy-gateway/gateway-2:
+    proxy:
+      listeners:
+      - address: null
+        name: envoy-gateway/gateway-2/http-1
+        ports:
+        - containerPort: 10443
+          name: https-443
+          protocol: HTTPS
+          servicePort: 443
+      metadata:
+        labels:
+          gateway.envoyproxy.io/owning-gateway-name: gateway-2
+          gateway.envoyproxy.io/owning-gateway-namespace: envoy-gateway
+      name: envoy-gateway/gateway-2
+  envoy-gateway/gateway-3:
+    proxy:
+      listeners:
+      - address: null
+        name: envoy-gateway/gateway-3/http-1
+        ports:
+        - containerPort: 10443
+          name: https-443
+          protocol: HTTPS
+          servicePort: 443
+      metadata:
+        labels:
+          gateway.envoyproxy.io/owning-gateway-name: gateway-3
+          gateway.envoyproxy.io/owning-gateway-namespace: envoy-gateway
+      name: envoy-gateway/gateway-3
 xdsIR:
   envoy-gateway/gateway-1:
     accessLog:
@@ -194,3 +369,57 @@ xdsIR:
         escapedSlashesAction: UnescapeAndRedirect
         mergeSlashes: true
       port: 8080
+  envoy-gateway/gateway-2:
+    accessLog:
+      text:
+      - path: /dev/stdout
+    http:
+    - address: 0.0.0.0
+      hostnames:
+      - '*'
+      isHTTP2: false
+      metadata:
+        kind: Gateway
+        name: gateway-2
+        namespace: envoy-gateway
+        sectionName: http-1
+      name: envoy-gateway/gateway-2/http-1
+      path:
+        escapedSlashesAction: UnescapeAndRedirect
+        mergeSlashes: true
+      port: 10443
+      tls:
+        alpnProtocols: []
+        certificates:
+        - name: envoy-gateway/tls-secret-1
+          privateKey: '[redacted]'
+          serverCertificate: 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
+        maxVersion: "1.3"
+        minVersion: "1.2"
+  envoy-gateway/gateway-3:
+    accessLog:
+      text:
+      - path: /dev/stdout
+    http:
+    - address: 0.0.0.0
+      hostnames:
+      - '*'
+      isHTTP2: false
+      metadata:
+        kind: Gateway
+        name: gateway-3
+        namespace: envoy-gateway
+        sectionName: http-1
+      name: envoy-gateway/gateway-3/http-1
+      path:
+        escapedSlashesAction: UnescapeAndRedirect
+        mergeSlashes: true
+      port: 10443
+      tls:
+        alpnProtocols: null
+        certificates:
+        - name: envoy-gateway/tls-secret-1
+          privateKey: '[redacted]'
+          serverCertificate: 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
+        maxVersion: "1.3"
+        minVersion: "1.2"
diff --git a/release-notes/current.yaml b/release-notes/current.yaml
index dc452458a21..9288e5266fc 100644
--- a/release-notes/current.yaml
+++ b/release-notes/current.yaml
@@ -3,6 +3,8 @@ date: Pending
 # Changes that are expected to cause an incompatibility with previous versions, such as deletions or modifications to existing APIs.
 breaking changes: |
   The Container `ports` field of the gateway instance has been removed, which will cause the gateway Pod to be rebuilt when upgrading the version.
+  ClientTrafficPolicy previously treated an empty TLS ALPNProtocols list as being undefined and applied Envoy Gateway defaults.
+  An empty TLS ALPNProtocols list is now treated as user-defined disablement of the TLS ALPN extension.
 
 # Updates addressing vulnerabilities, security flaws, or compliance requirements.
 security updates: |
diff --git a/site/content/en/latest/api/extension_types.md b/site/content/en/latest/api/extension_types.md
index 77a28384c06..99986f54b1f 100644
--- a/site/content/en/latest/api/extension_types.md
+++ b/site/content/en/latest/api/extension_types.md
@@ -407,7 +407,7 @@ _Appears in:_
 | `ciphers` | _string array_ |  false  | Ciphers specifies the set of cipher suites supported when<br />negotiating TLS 1.0 - 1.2. This setting has no effect for TLS 1.3.<br />In non-FIPS Envoy Proxy builds the default cipher list is:<br />- [ECDHE-ECDSA-AES128-GCM-SHA256\|ECDHE-ECDSA-CHACHA20-POLY1305]<br />- [ECDHE-RSA-AES128-GCM-SHA256\|ECDHE-RSA-CHACHA20-POLY1305]<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384<br />In builds using BoringSSL FIPS the default cipher list is:<br />- ECDHE-ECDSA-AES128-GCM-SHA256<br />- ECDHE-RSA-AES128-GCM-SHA256<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384 |
 | `ecdhCurves` | _string array_ |  false  | ECDHCurves specifies the set of supported ECDH curves.<br />In non-FIPS Envoy Proxy builds the default curves are:<br />- X25519<br />- P-256<br />In builds using BoringSSL FIPS the default curve is:<br />- P-256 |
 | `signatureAlgorithms` | _string array_ |  false  | SignatureAlgorithms specifies which signature algorithms the listener should<br />support. |
-| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener. By default h2 and http/1.1 are enabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
+| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener or used by the proxy to connect to the backend.<br />Defaults:<br />1. HTTPS Routes: h2 and http/1.1 are enabled in listener context.<br />2. Other Routes: ALPN is disabled.<br />3. Backends: proxy uses the appropriate ALPN options for the backend protocol.<br />When an empty list is provided, the ALPN TLS extension is disabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
 
 
 #### BackendTrafficPolicy
@@ -601,7 +601,7 @@ _Appears in:_
 | `ciphers` | _string array_ |  false  | Ciphers specifies the set of cipher suites supported when<br />negotiating TLS 1.0 - 1.2. This setting has no effect for TLS 1.3.<br />In non-FIPS Envoy Proxy builds the default cipher list is:<br />- [ECDHE-ECDSA-AES128-GCM-SHA256\|ECDHE-ECDSA-CHACHA20-POLY1305]<br />- [ECDHE-RSA-AES128-GCM-SHA256\|ECDHE-RSA-CHACHA20-POLY1305]<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384<br />In builds using BoringSSL FIPS the default cipher list is:<br />- ECDHE-ECDSA-AES128-GCM-SHA256<br />- ECDHE-RSA-AES128-GCM-SHA256<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384 |
 | `ecdhCurves` | _string array_ |  false  | ECDHCurves specifies the set of supported ECDH curves.<br />In non-FIPS Envoy Proxy builds the default curves are:<br />- X25519<br />- P-256<br />In builds using BoringSSL FIPS the default curve is:<br />- P-256 |
 | `signatureAlgorithms` | _string array_ |  false  | SignatureAlgorithms specifies which signature algorithms the listener should<br />support. |
-| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener. By default h2 and http/1.1 are enabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
+| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener or used by the proxy to connect to the backend.<br />Defaults:<br />1. HTTPS Routes: h2 and http/1.1 are enabled in listener context.<br />2. Other Routes: ALPN is disabled.<br />3. Backends: proxy uses the appropriate ALPN options for the backend protocol.<br />When an empty list is provided, the ALPN TLS extension is disabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
 | `session` | _[Session](#session)_ |  false  | Session defines settings related to TLS session management. |
 
 
@@ -4047,7 +4047,7 @@ _Appears in:_
 | `ciphers` | _string array_ |  false  | Ciphers specifies the set of cipher suites supported when<br />negotiating TLS 1.0 - 1.2. This setting has no effect for TLS 1.3.<br />In non-FIPS Envoy Proxy builds the default cipher list is:<br />- [ECDHE-ECDSA-AES128-GCM-SHA256\|ECDHE-ECDSA-CHACHA20-POLY1305]<br />- [ECDHE-RSA-AES128-GCM-SHA256\|ECDHE-RSA-CHACHA20-POLY1305]<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384<br />In builds using BoringSSL FIPS the default cipher list is:<br />- ECDHE-ECDSA-AES128-GCM-SHA256<br />- ECDHE-RSA-AES128-GCM-SHA256<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384 |
 | `ecdhCurves` | _string array_ |  false  | ECDHCurves specifies the set of supported ECDH curves.<br />In non-FIPS Envoy Proxy builds the default curves are:<br />- X25519<br />- P-256<br />In builds using BoringSSL FIPS the default curve is:<br />- P-256 |
 | `signatureAlgorithms` | _string array_ |  false  | SignatureAlgorithms specifies which signature algorithms the listener should<br />support. |
-| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener. By default h2 and http/1.1 are enabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
+| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener or used by the proxy to connect to the backend.<br />Defaults:<br />1. HTTPS Routes: h2 and http/1.1 are enabled in listener context.<br />2. Other Routes: ALPN is disabled.<br />3. Backends: proxy uses the appropriate ALPN options for the backend protocol.<br />When an empty list is provided, the ALPN TLS extension is disabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
 
 
 #### TLSVersion
diff --git a/site/content/zh/latest/api/extension_types.md b/site/content/zh/latest/api/extension_types.md
index 77a28384c06..99986f54b1f 100644
--- a/site/content/zh/latest/api/extension_types.md
+++ b/site/content/zh/latest/api/extension_types.md
@@ -407,7 +407,7 @@ _Appears in:_
 | `ciphers` | _string array_ |  false  | Ciphers specifies the set of cipher suites supported when<br />negotiating TLS 1.0 - 1.2. This setting has no effect for TLS 1.3.<br />In non-FIPS Envoy Proxy builds the default cipher list is:<br />- [ECDHE-ECDSA-AES128-GCM-SHA256\|ECDHE-ECDSA-CHACHA20-POLY1305]<br />- [ECDHE-RSA-AES128-GCM-SHA256\|ECDHE-RSA-CHACHA20-POLY1305]<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384<br />In builds using BoringSSL FIPS the default cipher list is:<br />- ECDHE-ECDSA-AES128-GCM-SHA256<br />- ECDHE-RSA-AES128-GCM-SHA256<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384 |
 | `ecdhCurves` | _string array_ |  false  | ECDHCurves specifies the set of supported ECDH curves.<br />In non-FIPS Envoy Proxy builds the default curves are:<br />- X25519<br />- P-256<br />In builds using BoringSSL FIPS the default curve is:<br />- P-256 |
 | `signatureAlgorithms` | _string array_ |  false  | SignatureAlgorithms specifies which signature algorithms the listener should<br />support. |
-| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener. By default h2 and http/1.1 are enabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
+| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener or used by the proxy to connect to the backend.<br />Defaults:<br />1. HTTPS Routes: h2 and http/1.1 are enabled in listener context.<br />2. Other Routes: ALPN is disabled.<br />3. Backends: proxy uses the appropriate ALPN options for the backend protocol.<br />When an empty list is provided, the ALPN TLS extension is disabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
 
 
 #### BackendTrafficPolicy
@@ -601,7 +601,7 @@ _Appears in:_
 | `ciphers` | _string array_ |  false  | Ciphers specifies the set of cipher suites supported when<br />negotiating TLS 1.0 - 1.2. This setting has no effect for TLS 1.3.<br />In non-FIPS Envoy Proxy builds the default cipher list is:<br />- [ECDHE-ECDSA-AES128-GCM-SHA256\|ECDHE-ECDSA-CHACHA20-POLY1305]<br />- [ECDHE-RSA-AES128-GCM-SHA256\|ECDHE-RSA-CHACHA20-POLY1305]<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384<br />In builds using BoringSSL FIPS the default cipher list is:<br />- ECDHE-ECDSA-AES128-GCM-SHA256<br />- ECDHE-RSA-AES128-GCM-SHA256<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384 |
 | `ecdhCurves` | _string array_ |  false  | ECDHCurves specifies the set of supported ECDH curves.<br />In non-FIPS Envoy Proxy builds the default curves are:<br />- X25519<br />- P-256<br />In builds using BoringSSL FIPS the default curve is:<br />- P-256 |
 | `signatureAlgorithms` | _string array_ |  false  | SignatureAlgorithms specifies which signature algorithms the listener should<br />support. |
-| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener. By default h2 and http/1.1 are enabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
+| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener or used by the proxy to connect to the backend.<br />Defaults:<br />1. HTTPS Routes: h2 and http/1.1 are enabled in listener context.<br />2. Other Routes: ALPN is disabled.<br />3. Backends: proxy uses the appropriate ALPN options for the backend protocol.<br />When an empty list is provided, the ALPN TLS extension is disabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
 | `session` | _[Session](#session)_ |  false  | Session defines settings related to TLS session management. |
 
 
@@ -4047,7 +4047,7 @@ _Appears in:_
 | `ciphers` | _string array_ |  false  | Ciphers specifies the set of cipher suites supported when<br />negotiating TLS 1.0 - 1.2. This setting has no effect for TLS 1.3.<br />In non-FIPS Envoy Proxy builds the default cipher list is:<br />- [ECDHE-ECDSA-AES128-GCM-SHA256\|ECDHE-ECDSA-CHACHA20-POLY1305]<br />- [ECDHE-RSA-AES128-GCM-SHA256\|ECDHE-RSA-CHACHA20-POLY1305]<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384<br />In builds using BoringSSL FIPS the default cipher list is:<br />- ECDHE-ECDSA-AES128-GCM-SHA256<br />- ECDHE-RSA-AES128-GCM-SHA256<br />- ECDHE-ECDSA-AES256-GCM-SHA384<br />- ECDHE-RSA-AES256-GCM-SHA384 |
 | `ecdhCurves` | _string array_ |  false  | ECDHCurves specifies the set of supported ECDH curves.<br />In non-FIPS Envoy Proxy builds the default curves are:<br />- X25519<br />- P-256<br />In builds using BoringSSL FIPS the default curve is:<br />- P-256 |
 | `signatureAlgorithms` | _string array_ |  false  | SignatureAlgorithms specifies which signature algorithms the listener should<br />support. |
-| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener. By default h2 and http/1.1 are enabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
+| `alpnProtocols` | _[ALPNProtocol](#alpnprotocol) array_ |  false  | ALPNProtocols supplies the list of ALPN protocols that should be<br />exposed by the listener or used by the proxy to connect to the backend.<br />Defaults:<br />1. HTTPS Routes: h2 and http/1.1 are enabled in listener context.<br />2. Other Routes: ALPN is disabled.<br />3. Backends: proxy uses the appropriate ALPN options for the backend protocol.<br />When an empty list is provided, the ALPN TLS extension is disabled.<br />Supported values are:<br />- http/1.0<br />- http/1.1<br />- h2 |
 
 
 #### TLSVersion