Merge branch v2.11 into v3.1

.github/workflows/validate.yaml

@@ -8,7 +8,7 @@ on:
 env:
   GO_VERSION: '1.23'
   GOLANGCI_LINT_VERSION: v1.60.3
-  MISSSPELL_VERSION: v0.6.0
+  MISSPELL_VERSION: v0.6.0
 
 jobs:
 
@@ -29,8 +29,8 @@ jobs:
       - name: Install golangci-lint ${{ env.GOLANGCI_LINT_VERSION }}
         run: curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin ${GOLANGCI_LINT_VERSION}
 
-      - name: Install missspell ${{ env.MISSSPELL_VERSION }}
+      - name: Install misspell ${{ env.MISSPELL_VERSION }}
-        run: curl -sfL https://raw.githubusercontent.com/golangci/misspell/master/install-misspell.sh | sh -s -- -b $(go env GOPATH)/bin ${MISSSPELL_VERSION}
+        run: curl -sfL https://raw.githubusercontent.com/golangci/misspell/master/install-misspell.sh | sh -s -- -b $(go env GOPATH)/bin ${MISSPELL_VERSION}
 
       - name: Avoid generating webui
         run: touch webui/static/index.html

CHANGELOG.md

@@ -1,3 +1,23 @@
+## [v2.11.9](https://github.com/traefik/traefik/tree/v2.11.9) (2024-09-16)
+[All Commits](https://github.com/traefik/traefik/compare/v2.11.8...v2.11.9)
+
+**Bug fixes:**
+- **[acme]** Update go-acme/lego to v4.18.0 ([#11060](https://github.com/traefik/traefik/pull/11060) by [ldez](https://github.com/ldez))
+- **[acme]** Allow handling ACME challenges with custom routers ([#10981](https://github.com/traefik/traefik/pull/10981) by [rtribotte](https://github.com/rtribotte))
+- **[logs,middleware]** Make the keys of the accessLog.fields.names map case-insensitive ([#11040](https://github.com/traefik/traefik/pull/11040) by [SpecLad](https://github.com/SpecLad))
+- **[logs,middleware]** Ensure proper logs for aborted streaming responses ([#10819](https://github.com/traefik/traefik/pull/10819) by [hood](https://github.com/hood))
+- **[middleware,server]** Cleanup Connection headers before passing the middleware chain ([#11077](https://github.com/traefik/traefik/pull/11077) by [kevinpollet](https://github.com/kevinpollet))
+- **[plugins]** Upgrade paerser to v0.2.1 ([#11048](https://github.com/traefik/traefik/pull/11048) by [mmatur](https://github.com/mmatur))
+- **[server,tcp]** Prevent error logging when TCP WRR pool is empty ([#10989](https://github.com/traefik/traefik/pull/10989) by [kevinpollet](https://github.com/kevinpollet))
+- **[webui]** Upgrade webui dependencies ([#11031](https://github.com/traefik/traefik/pull/11031) by [mloiseleur](https://github.com/mloiseleur))
+
+**Documentation:**
+- **[acme]** Fix typo in multiple DNS challenge provider warning ([#11001](https://github.com/traefik/traefik/pull/11001) by [tired-engineer](https://github.com/tired-engineer))
+- **[k8s]** Update k8s quickstart permissions ([#11049](https://github.com/traefik/traefik/pull/11049) by [mmatur](https://github.com/mmatur))
+- **[metrics]** Remove documentation for unimplemented service retries metric  ([#10983](https://github.com/traefik/traefik/pull/10983) by [rtribotte](https://github.com/rtribotte))
+- **[middleware]** Unify tab titles ([#11072](https://github.com/traefik/traefik/pull/11072) by [jsoref](https://github.com/jsoref))
+- Give valid examples for exposing dashboard with default Helm values ([#11015](https://github.com/traefik/traefik/pull/11015) by [holysoles](https://github.com/holysoles))
+
 ## [v3.1.2](https://github.com/traefik/traefik/tree/v3.1.2) (2024-08-06)
 [All Commits](https://github.com/traefik/traefik/compare/v3.1.1...v3.1.2)
 

CODE_OF_CONDUCT.md

@@ -47,7 +47,7 @@ Further details of specific enforcement policies may be posted separately.
 
 Project maintainers who do not follow or enforce the Code of Conduct in good faith may face temporary or permanent repercussions as determined by other members of the project's leadership.
 
-When an inapropriate behavior is reported, maintainers will discuss on the Maintainer's Discord before marking the message as "abuse". 
+When an inappropriate behavior is reported, maintainers will discuss on the Maintainer's Discord before marking the message as "abuse". 
 This conversation beforehand avoids one-sided decisions.
 
 The first message will be edited and marked as abuse.

cmd/traefik/traefik.go

@@ -364,7 +364,7 @@ func setupServer(staticConfiguration *static.Configuration) (*server.Server, err
 
 			if _, ok := resolverNames[rt.TLS.CertResolver]; !ok {
 				log.Error().Err(err).Str(logs.RouterName, rtName).Str("certificateResolver", rt.TLS.CertResolver).
-					Msg("Router uses a non-existent certificate resolver")
+					Msg("Router uses a nonexistent certificate resolver")
 			}
 		}
 	})

docs/content/https/acme.md

@@ -298,7 +298,7 @@ Use the `DNS-01` challenge to generate and renew ACME certificates by provisioni
     
     Multiple DNS challenge provider are not supported with Traefik, but you can use `CNAME` to handle that.
     For example, if you have `example.org` (account foo) and `example.com` (account bar) you can create a CNAME on `example.org` called `_acme-challenge.example.org` pointing to `challenge.example.com`.
-    This way, you can obtain certificates for `example.com` with the `foo` account.
+    This way, you can obtain certificates for `example.org` with the `bar` account.
 
 !!! important
     A `provider` is mandatory.

docs/content/middlewares/http/inflightreq.md

@@ -278,7 +278,7 @@ spec:
       requestHost: true
 ```
 
-```yaml tab="Cosul Catalog"
+```yaml tab="Consul Catalog"
 - "traefik.http.middlewares.test-inflightreq.inflightreq.sourcecriterion.requesthost=true"
 ```
 

docs/content/middlewares/http/overview.md

@@ -24,7 +24,7 @@ whoami:
     - "traefik.http.routers.router1.middlewares=foo-add-prefix@docker"
 ```
 
-```yaml tab="Kubernetes IngressRoute"
+```yaml tab="IngressRoute"
 # As a Kubernetes Traefik IngressRoute
 ---
 apiVersion: traefik.io/v1alpha1

docs/content/middlewares/overview.md

@@ -35,7 +35,7 @@ whoami:
     - "traefik.http.routers.router1.middlewares=foo-add-prefix@docker"
 ```
 
-```yaml tab="Kubernetes IngressRoute"
+```yaml tab="IngressRoute"
 ---
 apiVersion: traefik.io/v1alpha1
 kind: Middleware

docs/content/middlewares/tcp/overview.md

@@ -24,7 +24,7 @@ whoami:
     - "traefik.tcp.routers.router1.middlewares=foo-ip-allowlist@docker"
 ```
 
-```yaml tab="Kubernetes IngressRoute"
+```yaml tab="IngressRoute"
 # As a Kubernetes Traefik IngressRoute
 ---
 apiVersion: traefik.io/v1alpha1

docs/content/migration/v1-to-v2.md

@@ -44,7 +44,7 @@ Then any router can refer to an instance of the wanted middleware.
       - "traefik.frontend.auth.basic.users=test:$$apr1$$H6uskkkW$$IgXLP6ewTrSuBkTrqE8wj/,test2:$$apr1$$d9hr9HBB$$4HxwgUir3HP4EsggP/QNo0"
     ```
 
-    ```yaml tab="K8s Ingress"
+    ```yaml tab="Ingress"
     apiVersion: networking.k8s.io/v1beta1
     kind: Ingress
     metadata:
@@ -107,7 +107,7 @@ Then any router can refer to an instance of the wanted middleware.
       - "traefik.http.middlewares.auth.basicauth.users=test:$$apr1$$H6uskkkW$$IgXLP6ewTrSuBkTrqE8wj/,test2:$$apr1$$d9hr9HBB$$4HxwgUir3HP4EsggP/QNo0"
     ```
 
-    ```yaml tab="K8s IngressRoute"
+    ```yaml tab="IngressRoute"
     # The definitions below require the definitions for the Middleware and IngressRoute kinds.
     # https://doc.traefik.io/traefik/reference/dynamic-configuration/kubernetes-crd/#definitions
     apiVersion: traefik.io/v1alpha1
@@ -278,7 +278,7 @@ Then, a [router's TLS field](../routing/routers/index.md#tls) can refer to one o
         ]
     ```
 
-    ```yaml tab="K8s IngressRoute"
+    ```yaml tab="IngressRoute"
     # The definitions below require the definitions for the TLSOption and IngressRoute kinds.
     # https://doc.traefik.io/traefik/reference/dynamic-configuration/kubernetes-crd/#definitions
     apiVersion: traefik.io/v1alpha1
@@ -442,7 +442,7 @@ To apply a redirection:
       traefik.http.middlewares.https_redirect.redirectscheme.permanent: true
     ```
 
-    ```yaml tab="K8s IngressRoute"
+    ```yaml tab="IngressRoute"
     apiVersion: traefik.io/v1alpha1
     kind: IngressRoute
     metadata:
@@ -561,7 +561,7 @@ with the path `/admin` stripped, e.g. to `http://<IP>:<port>/`. In this case, yo
       - "traefik.frontend.rule=Host:example.org;PathPrefixStrip:/admin"
     ```
 
-    ```yaml tab="Kubernetes Ingress"
+    ```yaml tab="Ingress"
     apiVersion: networking.k8s.io/v1beta1
     kind: Ingress
     metadata:
@@ -595,7 +595,7 @@ with the path `/admin` stripped, e.g. to `http://<IP>:<port>/`. In this case, yo
       - "traefik.http.middlewares.admin-stripprefix.stripprefix.prefixes=/admin"
     ```
 
-    ```yaml tab="Kubernetes IngressRoute"
+    ```yaml tab="IngressRoute"
     ---
     apiVersion: traefik.io/v1alpha1
     kind: IngressRoute

docs/content/operations/cli.md

@@ -33,7 +33,7 @@ traefik [--flag[=true|false| ]] [-f [true|false| ]]
 
 All flags are documented in the [(static configuration) CLI reference](../reference/static-configuration/cli.md).
 
-!!! info "Flags are case insensitive."
+!!! info "Flags are case-insensitive."
 
 ### `healthcheck`
 

docs/content/providers/overview.md

@@ -81,7 +81,7 @@ For the list of the providers names, see the [supported providers](#supported-pr
         - "traefik.http.routers.my-container.middlewares=add-foo-prefix@file"
     ```
 
-    ```yaml tab="Kubernetes Ingress Route"
+    ```yaml tab="IngressRoute"
     apiVersion: traefik.io/v1alpha1
     kind: IngressRoute
     metadata:
@@ -103,7 +103,7 @@ For the list of the providers names, see the [supported providers](#supported-pr
             # when the cross-provider syntax is used.
     ```
 
-    ```yaml tab="Kubernetes Ingress"
+    ```yaml tab="Ingress"
     apiVersion: traefik.io/v1alpha1
     kind: Middleware
     metadata:

docs/content/reference/dynamic-configuration/consul-catalog.md

@@ -8,7 +8,7 @@ description: "View the reference for performing dynamic configurations with Trae
 Dynamic configuration with Consul Catalog
 {: .subtitle }
 
-The labels are case insensitive.
+The labels are case-insensitive.
 
 ```yaml
 --8<-- "content/reference/dynamic-configuration/consul-catalog.yml"

docs/content/reference/dynamic-configuration/ecs.md

@@ -8,7 +8,7 @@ description: "Learn how to do dynamic configuration in Traefik Proxy with AWS EC
 Dynamic configuration with ECS provider
 {: .subtitle }
 
-The labels are case insensitive.
+The labels are case-insensitive.
 
 ```yaml
 --8<-- "content/reference/dynamic-configuration/ecs.yml"

docs/content/reference/dynamic-configuration/nomad.md

@@ -8,7 +8,7 @@ description: "View the reference for performing dynamic configurations with Trae
 Dynamic configuration with Nomad Service Discovery
 {: .subtitle }
 
-The labels are case insensitive.
+The labels are case-insensitive.
 
 ```yaml
 --8<-- "content/reference/dynamic-configuration/nomad.yml"

docs/content/reference/static-configuration/cli-ref.md

@@ -117,9 +117,15 @@ Entry points definition. (Default: ```false```)
 `--entrypoints.<name>.address`:  
 Entry point address.
 
+`--entrypoints.<name>.allowacmebypass`:  
+Enables handling of ACME TLS and HTTP challenges with custom routers. (Default: ```false```)
+
 `--entrypoints.<name>.asdefault`:  
 Adds this EntryPoint to the list of default EntryPoints to be used on routers that don't have any Entrypoint defined. (Default: ```false```)
 
+`--entrypoints.<name>.forwardedheaders.connection`:  
+List of Connection headers that are allowed to pass through the middleware chain before being removed.
+
 `--entrypoints.<name>.forwardedheaders.insecure`:  
 Trust all forwarded headers. (Default: ```false```)
 

docs/content/reference/static-configuration/env-ref.md

@@ -117,9 +117,15 @@ Entry points definition. (Default: ```false```)
 `TRAEFIK_ENTRYPOINTS_<NAME>_ADDRESS`:  
 Entry point address.
 
+`TRAEFIK_ENTRYPOINTS_<NAME>_ALLOWACMEBYPASS`:  
+Enables handling of ACME TLS and HTTP challenges with custom routers. (Default: ```false```)
+
 `TRAEFIK_ENTRYPOINTS_<NAME>_ASDEFAULT`:  
 Adds this EntryPoint to the list of default EntryPoints to be used on routers that don't have any Entrypoint defined. (Default: ```false```)
 
+`TRAEFIK_ENTRYPOINTS_<NAME>_FORWARDEDHEADERS_CONNECTION`:  
+List of Connection headers that are allowed to pass through the middleware chain before being removed.
+
 `TRAEFIK_ENTRYPOINTS_<NAME>_FORWARDEDHEADERS_INSECURE`:  
 Trust all forwarded headers. (Default: ```false```)
 

docs/content/reference/static-configuration/file.toml

@@ -30,6 +30,7 @@
 [entryPoints]
   [entryPoints.EntryPoint0]
     address = "foobar"
+    allowACMEByPass = true
     reusePort = true
     asDefault = true
     [entryPoints.EntryPoint0.transport]
@@ -48,6 +49,7 @@
     [entryPoints.EntryPoint0.forwardedHeaders]
       insecure = true
       trustedIPs = ["foobar", "foobar"]
+      connection = ["foobar", "foobar"]
     [entryPoints.EntryPoint0.http]
       middlewares = ["foobar", "foobar"]
       encodeQuerySemicolons = true

docs/content/reference/static-configuration/file.yaml

@@ -35,6 +35,7 @@ tcpServersTransport:
 entryPoints:
   EntryPoint0:
     address: foobar
+    allowACMEByPass: true
     reusePort: true
     asDefault: true
     transport:
@@ -57,6 +58,9 @@ entryPoints:
       trustedIPs:
         - foobar
         - foobar
+      connection:
+        - foobar
+        - foobar
     http:
       redirections:
         entryPoint:

docs/content/routing/entrypoints.md

@@ -233,6 +233,35 @@ If both TCP and UDP are wanted for the same port, two entryPoints definitions ar
 
     Full details for how to specify `address` can be found in [net.Listen](https://golang.org/pkg/net/#Listen) (and [net.Dial](https://golang.org/pkg/net/#Dial)) of the doc for go.
 
+### AllowACMEByPass
+
+_Optional, Default=false_
+
+`allowACMEByPass` determines whether a user defined router can handle ACME TLS or HTTP challenges instead of the Traefik dedicated one.
+This option can be used when a Traefik instance has one or more certificate resolvers configured,
+but is also used to route challenges connections/requests to services that could also initiate their own ACME challenges.
+
+??? info "No Certificate Resolvers configured"
+
+    It is not necessary to use the `allowACMEByPass' option certificate option if no certificate resolver is defined.
+    In fact, Traefik will automatically allow ACME TLS or HTTP requests to be handled by custom routers in this case, since there can be no concurrency with its own challenge handlers.
+
+```yaml tab="File (YAML)"
+entryPoints:
+  foo:
+    allowACMEByPass: true
+```
+
+```toml tab="File (TOML)"
+[entryPoints.foo]
+  [entryPoints.foo.allowACMEByPass]
+    allowACMEByPass = true
+```
+
+```bash tab="CLI"
+--entryPoints.name.allowACMEByPass=true
+```
+
 ### ReusePort
 
 _Optional, Default=false_
@@ -500,6 +529,40 @@ You can configure Traefik to trust the forwarded headers information (`X-Forward
     --entryPoints.web.forwardedHeaders.insecure
     ```
 
+??? info "`forwardedHeaders.connection`"
+    
+    As per RFC7230, Traefik respects the Connection options from the client request.
+    By doing so, it removes any header field(s) listed in the request Connection header and the Connection header field itself when empty.
+    The removal happens as soon as the request is handled by Traefik,
+    thus the removed headers are not available when the request passes through the middleware chain.
+    The `connection` option lists the Connection headers allowed to passthrough the middleware chain before their removal.
+
+    ```yaml tab="File (YAML)"
+    ## Static configuration
+    entryPoints:
+      web:
+        address: ":80"
+        forwardedHeaders:
+          connection:
+            - foobar
+    ```
+
+    ```toml tab="File (TOML)"
+    ## Static configuration
+    [entryPoints]
+      [entryPoints.web]
+        address = ":80"
+
+        [entryPoints.web.forwardedHeaders]
+          connection = ["foobar"]
+    ```
+
+    ```bash tab="CLI"
+    ## Static configuration
+    --entryPoints.web.address=:80
+    --entryPoints.web.forwardedHeaders.connection=foobar
+    ```
+
 ### Transport
 
 #### `respondingTimeouts`

docs/content/routing/providers/consul-catalog.md

@@ -24,7 +24,7 @@ With Consul Catalog, Traefik can leverage tags attached to a service to generate
 
 !!! info "tags"
     
-    - tags are case insensitive.
+    - tags are case-insensitive.
     - The complete list of tags can be found [the reference page](../../reference/dynamic-configuration/consul-catalog.md)
 
 ### General

docs/content/routing/providers/docker.md

@@ -95,7 +95,7 @@ With Docker, Traefik can leverage labels attached to a container to generate rou
 
 !!! info "Labels"
 
-    - Labels are case insensitive.
+    - Labels are case-insensitive.
     - The complete list of labels can be found in [the reference page](../../reference/dynamic-configuration/docker.md).
 
 ### General

docs/content/routing/providers/ecs.md

@@ -22,7 +22,7 @@ With ECS, Traefik can leverage labels attached to a container to generate routin
 
 !!! info "labels"
     
-    - labels are case insensitive.
+    - labels are case-insensitive.
     - The complete list of labels can be found in [the reference page](../../reference/dynamic-configuration/ecs.md).
 
 ### General

docs/content/routing/providers/kv.md

@@ -12,7 +12,7 @@ A Story of key & values
 
 !!! info "Keys"
 
-    - Keys are case insensitive.
+    - Keys are case-insensitive.
     - The complete list of keys can be found in [the reference page](../../reference/dynamic-configuration/kv.md).
 
 ### Routers

docs/content/routing/providers/nomad.md

@@ -24,7 +24,7 @@ With Nomad, Traefik can leverage tags attached to a service to generate routing
 
 !!! info "tags"
 
-    - tags are case insensitive.
+    - tags are case-insensitive.
     - The complete list of tags can be found [the reference page](../../reference/dynamic-configuration/nomad.md)
 
 ### General

docs/content/routing/providers/swarm.md

@@ -118,7 +118,7 @@ With Docker Swarm, Traefik can leverage labels attached to a service to generate
 
 !!! info "Labels"
 
-    - Labels are case insensitive.
+    - Labels are case-insensitive.
     - The complete list of labels can be found in [the reference page](../../reference/dynamic-configuration/docker.md).
 
 ### General

docs/content/routing/routers/index.md

@@ -1197,7 +1197,7 @@ A value of `0` for the priority is ignored: `priority = 0` means that the defaul
     | Router-2 | ```ClientIP(`192.168.0.0/24`)```                            | 26       |
 
     Which means that requests from `192.168.0.12` would go to Router-2 even though Router-1 is intended to specifically handle them.
-    To achieve this intention, a priority (higher than 26) should be set on Router-1.
+    To achieve this intention, a priority (greater than 26) should be set on Router-1.
 
 ??? example "Setting priorities -- using the [File Provider](../../providers/file.md)"
 

docs/content/user-guides/docker-compose/acme-dns/index.md

@@ -1,6 +1,6 @@
 ---
 title: "Traefik Docker DNS Challenge Documentation"
-description: "Learn how to create a certificate with the Let's Encrypt DNS challenge to use HTTPS on a Service exposed with Traefik Proxy. Read the tehnical documentation."
+description: "Learn how to create a certificate with the Let's Encrypt DNS challenge to use HTTPS on a Service exposed with Traefik Proxy. Read the technical documentation."
 ---
 
 # Docker-compose with Let's Encrypt: DNS Challenge

integration/fixtures/headers/connection_hop_by_hop_headers.toml

@@ -0,0 +1,37 @@
+[global]
+  checkNewVersion = false
+  sendAnonymousUsage = false
+
+[log]
+  level = "DEBUG"
+
+# Limiting the Logs to Specific Fields
+[accessLog]
+  format = "json"
+  filePath = "access.log"
+
+  [accessLog.fields.headers.names]
+    "Foo" = "keep"
+    "Bar" = "keep"
+
+[entryPoints]
+  [entryPoints.web]
+    address = ":8000"
+  [entryPoints.web.forwardedHeaders]
+    insecure = true
+    connection = ["Foo"]
+
+[providers.file]
+  filename = "{{ .SelfFilename }}"
+
+## dynamic configuration ##
+
+[http.routers]
+  [http.routers.router1]
+    rule = "Host(`test.localhost`)"
+    service = "service1"
+
+[http.services]
+  [http.services.service1.loadBalancer]
+    [[http.services.service1.loadBalancer.servers]]
+      url = "http://127.0.0.1:9000"

integration/fixtures/https/clientca/README.md

@@ -48,7 +48,7 @@ openssl genrsa -out client3.key 2048
 # Locality Name (eg, city) []:.
 # Organization Name (eg, company) [Internet Widgits Pty Ltd]:.
 # Organizational Unit Name (eg, section) []:.
-# Common Name (e.g. server FQDN or YOUR name) []:clien1.example.com
+# Common Name (e.g. server FQDN or YOUR name) []:client1.example.com
 # Email Address []:.
 # 
 # Please enter the following 'extra' attributes
@@ -58,7 +58,7 @@ openssl genrsa -out client3.key 2048
 # Issuer
 #   CN = ca1.example.com
 # Subject
-#   CN = clien1.example.com
+#   CN = client1.example.com
 openssl req -key client1.key -new -out client1.csr
 
 # Country Name (2 letter code) [AU]:.

integration/headers_test.go

@@ -4,6 +4,7 @@ import (
 	"net"
 	"net/http"
 	"net/http/httptest"
+	"os"
 	"testing"
 	"time"
 
@@ -20,6 +21,11 @@ func TestHeadersSuite(t *testing.T) {
 	suite.Run(t, new(HeadersSuite))
 }
 
+func (s *HeadersSuite) TearDownTest() {
+	s.displayTraefikLogFile(traefikTestLogFile)
+	_ = os.Remove(traefikTestAccessLogFile)
+}
+
 func (s *HeadersSuite) TestSimpleConfiguration() {
 	s.traefikCmd(withConfigFile("fixtures/headers/basic.toml"))
 
@@ -62,6 +68,53 @@ func (s *HeadersSuite) TestReverseProxyHeaderRemoved() {
 	require.NoError(s.T(), err)
 }
 
+func (s *HeadersSuite) TestConnectionHopByHop() {
+	file := s.adaptFile("fixtures/headers/connection_hop_by_hop_headers.toml", struct{}{})
+	s.traefikCmd(withConfigFile(file))
+
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, found := r.Header["X-Forwarded-For"]
+		assert.True(s.T(), found)
+		xHost, found := r.Header["X-Forwarded-Host"]
+		assert.True(s.T(), found)
+		assert.Equal(s.T(), "localhost", xHost[0])
+
+		_, found = r.Header["Foo"]
+		assert.False(s.T(), found)
+		_, found = r.Header["Bar"]
+		assert.False(s.T(), found)
+	})
+
+	listener, err := net.Listen("tcp", "127.0.0.1:9000")
+	require.NoError(s.T(), err)
+
+	ts := &httptest.Server{
+		Listener: listener,
+		Config:   &http.Server{Handler: handler},
+	}
+	ts.Start()
+	defer ts.Close()
+
+	req, err := http.NewRequest(http.MethodGet, "http://127.0.0.1:8000/", nil)
+	require.NoError(s.T(), err)
+	req.Host = "test.localhost"
+	req.Header = http.Header{
+		"Connection":       {"Foo,Bar,X-Forwarded-For,X-Forwarded-Host"},
+		"Foo":              {"bar"},
+		"Bar":              {"foo"},
+		"X-Forwarded-Host": {"localhost"},
+	}
+
+	err = try.Request(req, time.Second, try.StatusCodeIs(http.StatusOK))
+	require.NoError(s.T(), err)
+
+	accessLog, err := os.ReadFile(traefikTestAccessLogFile)
+	require.NoError(s.T(), err)
+
+	assert.Contains(s.T(), string(accessLog), "\"request_Foo\":\"bar\"")
+	assert.NotContains(s.T(), string(accessLog), "\"request_Bar\":\"\"")
+}
+
 func (s *HeadersSuite) TestCorsResponses() {
 	file := s.adaptFile("fixtures/headers/cors.toml", struct{}{})
 	s.traefikCmd(withConfigFile(file))

integration/log_rotation_test.go

@@ -24,7 +24,7 @@ const traefikTestAccessLogFileRotated = traefikTestAccessLogFile + ".rotated"
 // Log rotation integration test suite.
 type LogRotationSuite struct{ BaseSuite }
 
-func TestLogRorationSuite(t *testing.T) {
+func TestLogRotationSuite(t *testing.T) {
 	suite.Run(t, new(LogRotationSuite))
 }
 

integration/simple_test.go

@@ -1382,7 +1382,7 @@ func (s *SimpleSuite) TestDebugLog() {
 
 	req, err := http.NewRequest(http.MethodGet, "http://localhost:8000/whoami", http.NoBody)
 	require.NoError(s.T(), err)
-	req.Header.Set("Autorization", "Bearer ThisIsABearerToken")
+	req.Header.Set("Authorization", "Bearer ThisIsABearerToken")
 
 	response, err := http.DefaultClient.Do(req)
 	require.NoError(s.T(), err)

pkg/config/kv/kv_node_test.go

@@ -71,7 +71,7 @@ func TestDecodeToNode(t *testing.T) {
 			desc: "several entries, level 0",
 			in: map[string]string{
 				"traefik":  "bar",
-				"traefic": "bur",
+				"traefik_": "bur",
 			},
 			expected: expected{error: true},
 		},
@@ -120,7 +120,7 @@ func TestDecodeToNode(t *testing.T) {
 			}},
 		},
 		{
-			desc: "several entries, level 2, case insensitive",
+			desc: "several entries, level 2, case-insensitive",
 			in: map[string]string{
 				"traefik/foo/aaa": "bar",
 				"traefik/Foo/bbb": "bur",

pkg/config/static/entrypoints.go

@@ -12,6 +12,7 @@ import (
 // EntryPoint holds the entry point configuration.
 type EntryPoint struct {
 	Address          string                `description:"Entry point address." json:"address,omitempty" toml:"address,omitempty" yaml:"address,omitempty"`
+	AllowACMEByPass  bool                  `description:"Enables handling of ACME TLS and HTTP challenges with custom routers." json:"allowACMEByPass,omitempty" toml:"allowACMEByPass,omitempty" yaml:"allowACMEByPass,omitempty"`
 	ReusePort        bool                  `description:"Enables EntryPoints from the same or different processes listening on the same TCP/UDP port." json:"reusePort,omitempty" toml:"reusePort,omitempty" yaml:"reusePort,omitempty"`
 	AsDefault        bool                  `description:"Adds this EntryPoint to the list of default EntryPoints to be used on routers that don't have any Entrypoint defined." json:"asDefault,omitempty" toml:"asDefault,omitempty" yaml:"asDefault,omitempty"`
 	Transport        *EntryPointsTransport `description:"Configures communication between clients and Traefik." json:"transport,omitempty" toml:"transport,omitempty" yaml:"transport,omitempty" export:"true"`
@@ -111,6 +112,7 @@ type TLSConfig struct {
 type ForwardedHeaders struct {
 	Insecure   bool     `description:"Trust all forwarded headers." json:"insecure,omitempty" toml:"insecure,omitempty" yaml:"insecure,omitempty" export:"true"`
 	TrustedIPs []string `description:"Trust only forwarded headers from selected IPs." json:"trustedIPs,omitempty" toml:"trustedIPs,omitempty" yaml:"trustedIPs,omitempty"`
+	Connection []string `description:"List of Connection headers that are allowed to pass through the middleware chain before being removed." json:"connection,omitempty" toml:"connection,omitempty" yaml:"connection,omitempty"`
 }
 
 // ProxyProtocol contains Proxy-Protocol configuration.

pkg/ip/strategy_test.go

@@ -46,7 +46,7 @@ func TestDepthStrategy_GetIP(t *testing.T) {
 			expected:      "10.0.0.3",
 		},
 		{
-			desc:          "Use non existing depth in XForwardedFor",
+			desc:          "Use nonexistent depth in XForwardedFor",
 			depth:         2,
 			xForwardedFor: "",
 			expected:      "",

pkg/middlewares/accesslog/logger.go

@@ -106,8 +106,20 @@ func NewHandler(config *types.AccessLog) (*Handler, error) {
 		Level:     logrus.InfoLevel,
 	}
 
-	// Transform headers names in config to a canonical form, to be used as is without further transformations.
+	// Transform header names to a canonical form, to be used as is without further transformations,
-	if config.Fields != nil && config.Fields.Headers != nil && len(config.Fields.Headers.Names) > 0 {
+	// and transform field names to lower case, to enable case-insensitive lookup.
+	if config.Fields != nil {
+		if len(config.Fields.Names) > 0 {
+			fields := map[string]string{}
+
+			for h, v := range config.Fields.Names {
+				fields[strings.ToLower(h)] = v
+			}
+
+			config.Fields.Names = fields
+		}
+
+		if config.Fields.Headers != nil && len(config.Fields.Headers.Names) > 0 {
 			fields := map[string]string{}
 
 			for h, v := range config.Fields.Headers.Names {
@@ -116,6 +128,7 @@ func NewHandler(config *types.AccessLog) (*Handler, error) {
 
 			config.Fields.Headers.Names = fields
 		}
+	}
 
 	logHandler := &Handler{
 		config:         config,
@@ -184,16 +197,6 @@ func (h *Handler) ServeHTTP(rw http.ResponseWriter, req *http.Request, next http
 		},
 	}
 
-	defer func() {
-		if h.config.BufferingSize > 0 {
-			h.logHandlerChan <- handlerParams{
-				logDataTable: logDataTable,
-			}
-			return
-		}
-		h.logTheRoundTrip(logDataTable)
-	}()
-
 	reqWithDataTable := req.WithContext(context.WithValue(req.Context(), DataTableKey, logDataTable))
 
 	core[RequestCount] = nextRequestCount()
@@ -238,12 +241,7 @@ func (h *Handler) ServeHTTP(rw http.ResponseWriter, req *http.Request, next http
 		return
 	}
 
-	next.ServeHTTP(rw, reqWithDataTable)
+	defer func() {
-
-	if _, ok := core[ClientUsername]; !ok {
-		core[ClientUsername] = usernameIfPresent(reqWithDataTable.URL)
-	}
-
 		logDataTable.DownstreamResponse = downstreamResponse{
 			headers: rw.Header().Clone(),
 		}
@@ -251,6 +249,22 @@ func (h *Handler) ServeHTTP(rw http.ResponseWriter, req *http.Request, next http
 		logDataTable.DownstreamResponse.status = capt.StatusCode()
 		logDataTable.DownstreamResponse.size = capt.ResponseSize()
 		logDataTable.Request.size = capt.RequestSize()
+
+		if _, ok := core[ClientUsername]; !ok {
+			core[ClientUsername] = usernameIfPresent(reqWithDataTable.URL)
+		}
+
+		if h.config.BufferingSize > 0 {
+			h.logHandlerChan <- handlerParams{
+				logDataTable: logDataTable,
+			}
+			return
+		}
+
+		h.logTheRoundTrip(logDataTable)
+	}()
+
+	next.ServeHTTP(rw, reqWithDataTable)
 }
 
 // Close closes the Logger (i.e. the file, drain logHandlerChan, etc).
@@ -334,7 +348,7 @@ func (h *Handler) logTheRoundTrip(logDataTable *LogData) {
 		fields := logrus.Fields{}
 
 		for k, v := range logDataTable.Core {
-			if h.config.Fields.Keep(k) {
+			if h.config.Fields.Keep(strings.ToLower(k)) {
 				fields[k] = v
 			}
 		}

pkg/middlewares/accesslog/logger_test.go

@@ -2,6 +2,7 @@ package accesslog
 
 import (
 	"bytes"
+	"context"
 	"crypto/tls"
 	"crypto/x509"
 	"crypto/x509/pkix"
@@ -24,6 +25,7 @@ import (
 	"github.com/stretchr/testify/require"
 	ptypes "github.com/traefik/paerser/types"
 	"github.com/traefik/traefik/v3/pkg/middlewares/capture"
+	"github.com/traefik/traefik/v3/pkg/middlewares/recovery"
 	"github.com/traefik/traefik/v3/pkg/types"
 )
 
@@ -164,7 +166,7 @@ func TestLoggerHeaderFields(t *testing.T) {
 			},
 		},
 		{
-			desc:     "with case insensitive match on header name",
+			desc:     "with case-insensitive match on header name",
 			header:   "User-Agent",
 			expected: types.AccessLogKeep,
 			accessLogFields: types.AccessLogFields{
@@ -465,6 +467,32 @@ func TestLoggerJSON(t *testing.T) {
 				RequestRefererHeader: assertString(testReferer),
 			},
 		},
+		{
+			desc: "fields and headers with unconventional letter case",
+			config: &types.AccessLog{
+				FilePath: "",
+				Format:   JSONFormat,
+				Fields: &types.AccessLogFields{
+					DefaultMode: "drop",
+					Names: map[string]string{
+						"rEqUeStHoSt": "keep",
+					},
+					Headers: &types.FieldHeaders{
+						DefaultMode: "drop",
+						Names: map[string]string{
+							"ReFeReR": "keep",
+						},
+					},
+				},
+			},
+			expected: map[string]func(t *testing.T, value interface{}){
+				RequestHost:          assertString(testHostname),
+				"level":              assertString("info"),
+				"msg":                assertString(""),
+				"time":               assertNotEmpty(),
+				RequestRefererHeader: assertString(testReferer),
+			},
+		},
 	}
 
 	for _, test := range testCases {
@@ -496,6 +524,64 @@ func TestLoggerJSON(t *testing.T) {
 	}
 }
 
+func TestLogger_AbortedRequest(t *testing.T) {
+	expected := map[string]func(t *testing.T, value interface{}){
+		RequestContentSize:             assertFloat64(0),
+		RequestHost:                    assertString(testHostname),
+		RequestAddr:                    assertString(testHostname),
+		RequestMethod:                  assertString(testMethod),
+		RequestPath:                    assertString(""),
+		RequestProtocol:                assertString(testProto),
+		RequestScheme:                  assertString(testScheme),
+		RequestPort:                    assertString("-"),
+		DownstreamStatus:               assertFloat64(float64(200)),
+		DownstreamContentSize:          assertFloat64(float64(40)),
+		RequestRefererHeader:           assertString(testReferer),
+		RequestUserAgentHeader:         assertString(testUserAgent),
+		ServiceURL:                     assertString("http://stream"),
+		ServiceAddr:                    assertString("127.0.0.1"),
+		ServiceName:                    assertString("stream"),
+		ClientUsername:                 assertString(testUsername),
+		ClientHost:                     assertString(testHostname),
+		ClientPort:                     assertString(strconv.Itoa(testPort)),
+		ClientAddr:                     assertString(fmt.Sprintf("%s:%d", testHostname, testPort)),
+		"level":                        assertString("info"),
+		"msg":                          assertString(""),
+		RequestCount:                   assertFloat64NotZero(),
+		Duration:                       assertFloat64NotZero(),
+		Overhead:                       assertFloat64NotZero(),
+		RetryAttempts:                  assertFloat64(float64(0)),
+		"time":                         assertNotEmpty(),
+		StartLocal:                     assertNotEmpty(),
+		StartUTC:                       assertNotEmpty(),
+		"downstream_Content-Type":      assertString("text/plain"),
+		"downstream_Transfer-Encoding": assertString("chunked"),
+		"downstream_Cache-Control":     assertString("no-cache"),
+	}
+
+	config := &types.AccessLog{
+		FilePath: filepath.Join(t.TempDir(), logFileNameSuffix),
+		Format:   JSONFormat,
+	}
+	doLoggingWithAbortedStream(t, config)
+
+	logData, err := os.ReadFile(config.FilePath)
+	require.NoError(t, err)
+
+	jsonData := make(map[string]interface{})
+	err = json.Unmarshal(logData, &jsonData)
+	require.NoError(t, err)
+
+	assert.Equal(t, len(expected), len(jsonData))
+
+	for field, assertion := range expected {
+		assertion(t, jsonData[field])
+		if t.Failed() {
+			return
+		}
+	}
+}
+
 func TestNewLogHandlerOutputStdout(t *testing.T) {
 	testCases := []struct {
 		desc        string
@@ -832,3 +918,89 @@ func logWriterTestHandlerFunc(rw http.ResponseWriter, r *http.Request) {
 
 	rw.WriteHeader(testStatus)
 }
+
+func doLoggingWithAbortedStream(t *testing.T, config *types.AccessLog) {
+	t.Helper()
+
+	logger, err := NewHandler(config)
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		err := logger.Close()
+		require.NoError(t, err)
+	})
+
+	if config.FilePath != "" {
+		_, err = os.Stat(config.FilePath)
+		require.NoError(t, err, "logger should create "+config.FilePath)
+	}
+
+	reqContext, cancelRequest := context.WithCancel(context.Background())
+
+	req := &http.Request{
+		Header: map[string][]string{
+			"User-Agent": {testUserAgent},
+			"Referer":    {testReferer},
+		},
+		Proto:      testProto,
+		Host:       testHostname,
+		Method:     testMethod,
+		RemoteAddr: fmt.Sprintf("%s:%d", testHostname, testPort),
+		URL: &url.URL{
+			User: url.UserPassword(testUsername, ""),
+		},
+		Body: nil,
+	}
+
+	req = req.WithContext(reqContext)
+
+	chain := alice.New()
+	chain = chain.Append(func(next http.Handler) (http.Handler, error) {
+		return recovery.New(context.Background(), next)
+	})
+	chain = chain.Append(capture.Wrap)
+	chain = chain.Append(WrapHandler(logger))
+
+	service := NewFieldHandler(http.HandlerFunc(streamBackend), ServiceURL, "http://stream", nil)
+	service = NewFieldHandler(service, ServiceAddr, "127.0.0.1", nil)
+	service = NewFieldHandler(service, ServiceName, "stream", AddServiceFields)
+
+	handler, err := chain.Then(service)
+	require.NoError(t, err)
+
+	go func() {
+		time.Sleep(499 * time.Millisecond)
+		cancelRequest()
+	}()
+
+	handler.ServeHTTP(httptest.NewRecorder(), req)
+}
+
+func streamBackend(rw http.ResponseWriter, r *http.Request) {
+	// Get the Flusher to flush the response to the client
+	flusher, ok := rw.(http.Flusher)
+	if !ok {
+		http.Error(rw, "Streaming unsupported!", http.StatusInternalServerError)
+		return
+	}
+
+	// Set the headers for streaming
+	rw.Header().Set("Content-Type", "text/plain")
+	rw.Header().Set("Transfer-Encoding", "chunked")
+	rw.Header().Set("Cache-Control", "no-cache")
+
+	for {
+		time.Sleep(100 * time.Millisecond)
+
+		select {
+		case <-r.Context().Done():
+			panic(http.ErrAbortHandler)
+
+		default:
+			if _, err := fmt.Fprint(rw, "FOOBAR!!!!"); err != nil {
+				http.Error(rw, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			flusher.Flush()
+		}
+	}
+}

pkg/middlewares/auth/connectionheader.go

@@ -1,4 +1,4 @@
-package connectionheader
+package auth
 
 import (
 	"net/http"

pkg/middlewares/auth/connectionheader_test.go

@@ -1,4 +1,4 @@
-package connectionheader
+package auth
 
 import (
 	"net/http"

pkg/middlewares/auth/forward.go

@@ -13,7 +13,6 @@ import (
 
 	"github.com/traefik/traefik/v3/pkg/config/dynamic"
 	"github.com/traefik/traefik/v3/pkg/middlewares"
-	"github.com/traefik/traefik/v3/pkg/middlewares/connectionheader"
 	"github.com/traefik/traefik/v3/pkg/middlewares/observability"
 	"github.com/traefik/traefik/v3/pkg/tracing"
 	"github.com/traefik/traefik/v3/pkg/types"
@@ -121,7 +120,7 @@ func (fa *forwardAuth) GetTracingInformation() (string, string, trace.SpanKind)
 func (fa *forwardAuth) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 	logger := middlewares.GetLogger(req.Context(), fa.name, typeNameForward)
 
-	req = connectionheader.Remove(req)
+	req = Remove(req)
 
 	forwardReq, err := http.NewRequestWithContext(req.Context(), http.MethodGet, fa.address, nil)
 	if err != nil {

pkg/middlewares/customerrors/custom_errors.go

@@ -235,7 +235,7 @@ func (cc *codeCatcher) Flush() {
 	// since we want to serve the ones from the error page,
 	// so we just don't flush.
 	// (e.g., To prevent superfluous WriteHeader on request with a
-	// `Transfert-Encoding: chunked` header).
+	// `Transfer-Encoding: chunked` header).
 	if cc.caughtFilteredCode {
 		return
 	}

pkg/middlewares/forwardedheaders/forwarded_header.go

@@ -3,10 +3,13 @@ package forwardedheaders
 import (
 	"net"
 	"net/http"
+	"net/textproto"
 	"os"
+	"slices"
 	"strings"
 
 	"github.com/traefik/traefik/v3/pkg/ip"
+	"golang.org/x/net/http/httpguts"
 )
 
 const (
@@ -43,18 +46,19 @@ var xHeaders = []string{
 // it first removes all the existing values for those headers if the remote address is not one of the trusted ones.
 type XForwarded struct {
 	insecure          bool
-	trustedIps []string
+	trustedIPs        []string
+	connectionHeaders []string
 	ipChecker         *ip.Checker
 	next              http.Handler
 	hostname          string
 }
 
 // NewXForwarded creates a new XForwarded.
-func NewXForwarded(insecure bool, trustedIps []string, next http.Handler) (*XForwarded, error) {
+func NewXForwarded(insecure bool, trustedIPs []string, connectionHeaders []string, next http.Handler) (*XForwarded, error) {
 	var ipChecker *ip.Checker
-	if len(trustedIps) > 0 {
+	if len(trustedIPs) > 0 {
 		var err error
-		ipChecker, err = ip.NewChecker(trustedIps)
+		ipChecker, err = ip.NewChecker(trustedIPs)
 		if err != nil {
 			return nil, err
 		}
@@ -67,7 +71,8 @@ func NewXForwarded(insecure bool, trustedIps []string, next http.Handler) (*XFor
 
 	return &XForwarded{
 		insecure:          insecure,
-		trustedIps: trustedIps,
+		trustedIPs:        trustedIPs,
+		connectionHeaders: connectionHeaders,
 		ipChecker:         ipChecker,
 		next:              next,
 		hostname:          hostname,
@@ -189,9 +194,53 @@ func (x *XForwarded) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 	x.rewrite(r)
 
+	x.removeConnectionHeaders(r)
+
 	x.next.ServeHTTP(w, r)
 }
 
+func (x *XForwarded) removeConnectionHeaders(req *http.Request) {
+	var reqUpType string
+	if httpguts.HeaderValuesContainsToken(req.Header[connection], upgrade) {
+		reqUpType = unsafeHeader(req.Header).Get(upgrade)
+	}
+
+	var connectionHopByHopHeaders []string
+	for _, f := range req.Header[connection] {
+		for _, sf := range strings.Split(f, ",") {
+			if sf = textproto.TrimString(sf); sf != "" {
+				// Connection header cannot dictate to remove X- headers managed by Traefik,
+				// as per rfc7230 https://datatracker.ietf.org/doc/html/rfc7230#section-6.1,
+				// A proxy or gateway MUST ... and then remove the Connection header field itself
+				// (or replace it with the intermediary's own connection options for the forwarded message).
+				if slices.Contains(xHeaders, sf) {
+					continue
+				}
+
+				// Keep headers allowed through the middleware chain.
+				if slices.Contains(x.connectionHeaders, sf) {
+					connectionHopByHopHeaders = append(connectionHopByHopHeaders, sf)
+					continue
+				}
+
+				// Apply Connection header option.
+				req.Header.Del(sf)
+			}
+		}
+	}
+
+	if reqUpType != "" {
+		connectionHopByHopHeaders = append(connectionHopByHopHeaders, upgrade)
+		unsafeHeader(req.Header).Set(upgrade, reqUpType)
+	}
+	if len(connectionHopByHopHeaders) > 0 {
+		unsafeHeader(req.Header).Set(connection, strings.Join(connectionHopByHopHeaders, ","))
+		return
+	}
+
+	unsafeHeader(req.Header).Del(connection)
+}
+
 // unsafeHeader allows to manage Header values.
 // Must be used only when the header name is already a canonical key.
 type unsafeHeader map[string][]string

pkg/middlewares/forwardedheaders/forwarded_header_test.go

@@ -15,6 +15,7 @@ func TestServeHTTP(t *testing.T) {
 		desc              string
 		insecure          bool
 		trustedIps        []string
+		connectionHeaders []string
 		incomingHeaders   map[string][]string
 		remoteAddr        string
 		expectedHeaders   map[string]string
@@ -269,6 +270,196 @@ func TestServeHTTP(t *testing.T) {
 				xForwardedServer: "foo.com:8080",
 			},
 		},
+		{
+			desc:     "Untrusted: Connection header has no effect on X- forwarded headers",
+			insecure: false,
+			incomingHeaders: map[string][]string{
+				connection: {
+					xForwardedProto,
+					xForwardedFor,
+					xForwardedURI,
+					xForwardedMethod,
+					xForwardedHost,
+					xForwardedPort,
+					xForwardedTLSClientCert,
+					xForwardedTLSClientCertInfo,
+					xRealIP,
+				},
+				xForwardedProto:             {"foo"},
+				xForwardedFor:               {"foo"},
+				xForwardedURI:               {"foo"},
+				xForwardedMethod:            {"foo"},
+				xForwardedHost:              {"foo"},
+				xForwardedPort:              {"foo"},
+				xForwardedTLSClientCert:     {"foo"},
+				xForwardedTLSClientCertInfo: {"foo"},
+				xRealIP:                     {"foo"},
+			},
+			expectedHeaders: map[string]string{
+				xForwardedProto:             "http",
+				xForwardedFor:               "",
+				xForwardedURI:               "",
+				xForwardedMethod:            "",
+				xForwardedHost:              "",
+				xForwardedPort:              "80",
+				xForwardedTLSClientCert:     "",
+				xForwardedTLSClientCertInfo: "",
+				xRealIP:                     "",
+				connection:                  "",
+			},
+		},
+		{
+			desc:     "Trusted (insecure): Connection header has no effect on X- forwarded headers",
+			insecure: true,
+			incomingHeaders: map[string][]string{
+				connection: {
+					xForwardedProto,
+					xForwardedFor,
+					xForwardedURI,
+					xForwardedMethod,
+					xForwardedHost,
+					xForwardedPort,
+					xForwardedTLSClientCert,
+					xForwardedTLSClientCertInfo,
+					xRealIP,
+				},
+				xForwardedProto:             {"foo"},
+				xForwardedFor:               {"foo"},
+				xForwardedURI:               {"foo"},
+				xForwardedMethod:            {"foo"},
+				xForwardedHost:              {"foo"},
+				xForwardedPort:              {"foo"},
+				xForwardedTLSClientCert:     {"foo"},
+				xForwardedTLSClientCertInfo: {"foo"},
+				xRealIP:                     {"foo"},
+			},
+			expectedHeaders: map[string]string{
+				xForwardedProto:             "foo",
+				xForwardedFor:               "foo",
+				xForwardedURI:               "foo",
+				xForwardedMethod:            "foo",
+				xForwardedHost:              "foo",
+				xForwardedPort:              "foo",
+				xForwardedTLSClientCert:     "foo",
+				xForwardedTLSClientCertInfo: "foo",
+				xRealIP:                     "foo",
+				connection:                  "",
+			},
+		},
+		{
+			desc:     "Untrusted and Connection: Connection header has no effect on X- forwarded headers",
+			insecure: false,
+			connectionHeaders: []string{
+				xForwardedProto,
+				xForwardedFor,
+				xForwardedURI,
+				xForwardedMethod,
+				xForwardedHost,
+				xForwardedPort,
+				xForwardedTLSClientCert,
+				xForwardedTLSClientCertInfo,
+				xRealIP,
+			},
+			incomingHeaders: map[string][]string{
+				connection: {
+					xForwardedProto,
+					xForwardedFor,
+					xForwardedURI,
+					xForwardedMethod,
+					xForwardedHost,
+					xForwardedPort,
+					xForwardedTLSClientCert,
+					xForwardedTLSClientCertInfo,
+					xRealIP,
+				},
+				xForwardedProto:             {"foo"},
+				xForwardedFor:               {"foo"},
+				xForwardedURI:               {"foo"},
+				xForwardedMethod:            {"foo"},
+				xForwardedHost:              {"foo"},
+				xForwardedPort:              {"foo"},
+				xForwardedTLSClientCert:     {"foo"},
+				xForwardedTLSClientCertInfo: {"foo"},
+				xRealIP:                     {"foo"},
+			},
+			expectedHeaders: map[string]string{
+				xForwardedProto:             "http",
+				xForwardedFor:               "",
+				xForwardedURI:               "",
+				xForwardedMethod:            "",
+				xForwardedHost:              "",
+				xForwardedPort:              "80",
+				xForwardedTLSClientCert:     "",
+				xForwardedTLSClientCertInfo: "",
+				xRealIP:                     "",
+				connection:                  "",
+			},
+		},
+		{
+			desc:     "Trusted (insecure) and Connection: Connection header has no effect on X- forwarded headers",
+			insecure: true,
+			connectionHeaders: []string{
+				xForwardedProto,
+				xForwardedFor,
+				xForwardedURI,
+				xForwardedMethod,
+				xForwardedHost,
+				xForwardedPort,
+				xForwardedTLSClientCert,
+				xForwardedTLSClientCertInfo,
+				xRealIP,
+			},
+			incomingHeaders: map[string][]string{
+				connection: {
+					xForwardedProto,
+					xForwardedFor,
+					xForwardedURI,
+					xForwardedMethod,
+					xForwardedHost,
+					xForwardedPort,
+					xForwardedTLSClientCert,
+					xForwardedTLSClientCertInfo,
+					xRealIP,
+				},
+				xForwardedProto:             {"foo"},
+				xForwardedFor:               {"foo"},
+				xForwardedURI:               {"foo"},
+				xForwardedMethod:            {"foo"},
+				xForwardedHost:              {"foo"},
+				xForwardedPort:              {"foo"},
+				xForwardedTLSClientCert:     {"foo"},
+				xForwardedTLSClientCertInfo: {"foo"},
+				xRealIP:                     {"foo"},
+			},
+			expectedHeaders: map[string]string{
+				xForwardedProto:             "foo",
+				xForwardedFor:               "foo",
+				xForwardedURI:               "foo",
+				xForwardedMethod:            "foo",
+				xForwardedHost:              "foo",
+				xForwardedPort:              "foo",
+				xForwardedTLSClientCert:     "foo",
+				xForwardedTLSClientCertInfo: "foo",
+				xRealIP:                     "foo",
+				connection:                  "",
+			},
+		},
+		{
+			desc: "Connection: one remove, and one passthrough header",
+			connectionHeaders: []string{
+				"foo",
+			},
+			incomingHeaders: map[string][]string{
+				connection: {
+					"foo",
+				},
+				"Foo": {"bar"},
+				"Bar": {"foo"},
+			},
+			expectedHeaders: map[string]string{
+				"Bar": "foo",
+			},
+		},
 	}
 
 	for _, test := range testCases {
@@ -299,7 +490,7 @@ func TestServeHTTP(t *testing.T) {
 				}
 			}
 
-			m, err := NewXForwarded(test.insecure, test.trustedIps,
+			m, err := NewXForwarded(test.insecure, test.trustedIps, test.connectionHeaders,
 				http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {}))
 			require.NoError(t, err)
 
@@ -382,3 +573,74 @@ func Test_isWebsocketRequest(t *testing.T) {
 		})
 	}
 }
+
+func TestConnection(t *testing.T) {
+	testCases := []struct {
+		desc              string
+		reqHeaders        map[string]string
+		connectionHeaders []string
+		expected          http.Header
+	}{
+		{
+			desc: "simple remove",
+			reqHeaders: map[string]string{
+				"Foo":      "bar",
+				connection: "foo",
+			},
+			expected: http.Header{},
+		},
+		{
+			desc: "remove and upgrade",
+			reqHeaders: map[string]string{
+				upgrade:    "test",
+				"Foo":      "bar",
+				connection: "upgrade,foo",
+			},
+			expected: http.Header{
+				upgrade:    []string{"test"},
+				connection: []string{"Upgrade"},
+			},
+		},
+		{
+			desc: "no remove",
+			reqHeaders: map[string]string{
+				"Foo":      "bar",
+				connection: "fii",
+			},
+			expected: http.Header{
+				"Foo": []string{"bar"},
+			},
+		},
+		{
+			desc: "no remove because connection header pass through",
+			reqHeaders: map[string]string{
+				"Foo":      "bar",
+				connection: "Foo",
+			},
+			connectionHeaders: []string{"Foo"},
+			expected: http.Header{
+				"Foo":      []string{"bar"},
+				connection: []string{"Foo"},
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			forwarded, err := NewXForwarded(true, nil, test.connectionHeaders, nil)
+			require.NoError(t, err)
+
+			req := httptest.NewRequest(http.MethodGet, "https://localhost", nil)
+
+			for k, v := range test.reqHeaders {
+				req.Header.Set(k, v)
+			}
+
+			forwarded.removeConnectionHeaders(req)
+
+			assert.Equal(t, test.expected, req.Header)
+		})
+	}
+}

pkg/middlewares/headers/headers.go

@@ -8,7 +8,6 @@ import (
 
 	"github.com/traefik/traefik/v3/pkg/config/dynamic"
 	"github.com/traefik/traefik/v3/pkg/middlewares"
-	"github.com/traefik/traefik/v3/pkg/middlewares/connectionheader"
 	"go.opentelemetry.io/otel/trace"
 )
 
@@ -46,12 +45,11 @@ func New(ctx context.Context, next http.Handler, cfg dynamic.Headers, name strin
 
 	if hasCustomHeaders || hasCorsHeaders {
 		logger.Debug().Msgf("Setting up customHeaders/Cors from %v", cfg)
-		h, err := NewHeader(nextHandler, cfg)
+		var err error
+		handler, err = NewHeader(nextHandler, cfg)
 		if err != nil {
 			return nil, err
 		}
-
-		handler = connectionheader.Remover(h)
 	}
 
 	return &headers{

pkg/provider/docker/builder_test.go

@@ -205,7 +205,7 @@ func withEndpointSpec(ops ...func(*swarm.EndpointSpec)) func(*swarm.Service) {
 	}
 }
 
-func modeDNSSR(spec *swarm.EndpointSpec) {
+func modeDNSRR(spec *swarm.EndpointSpec) {
 	spec.Mode = swarm.ResolutionModeDNSRR
 }
 

pkg/provider/docker/config_test.go

@@ -3976,7 +3976,7 @@ func TestDynConfBuilder_getIPAddress_swarm(t *testing.T) {
 		networks map[string]*network.Summary
 	}{
 		{
-			service:  swarmService(withEndpointSpec(modeDNSSR)),
+			service:  swarmService(withEndpointSpec(modeDNSRR)),
 			expected: "",
 			networks: map[string]*network.Summary{},
 		},

pkg/provider/docker/pswarm_test.go

@@ -114,7 +114,7 @@ func TestSwarmProvider_listServices(t *testing.T) {
 						"traefik.docker.network": "barnet",
 						"traefik.docker.LBSwarm": "true",
 					}),
-					withEndpointSpec(modeDNSSR)),
+					withEndpointSpec(modeDNSRR)),
 			},
 			dockerVersion:    "1.30",
 			networks:         []network.Summary{},
@@ -140,7 +140,7 @@ func TestSwarmProvider_listServices(t *testing.T) {
 						"traefik.docker.network": "barnet",
 						"traefik.docker.LBSwarm": "true",
 					}),
-					withEndpointSpec(modeDNSSR)),
+					withEndpointSpec(modeDNSRR)),
 			},
 			dockerVersion: "1.30",
 			networks: []network.Summary{
@@ -185,7 +185,7 @@ func TestSwarmProvider_listServices(t *testing.T) {
 					serviceLabels(map[string]string{
 						"traefik.docker.network": "barnet",
 					}),
-					withEndpointSpec(modeDNSSR)),
+					withEndpointSpec(modeDNSRR)),
 			},
 			tasks: []swarm.Task{
 				swarmTask("id1",

pkg/provider/docker/shared_test.go

@@ -86,7 +86,7 @@ func Test_getPort_swarm(t *testing.T) {
 	}{
 		{
 			service: swarmService(
-				withEndpointSpec(modeDNSSR),
+				withEndpointSpec(modeDNSRR),
 			),
 			networks:   map[string]*docker.NetworkResource{},
 			serverPort: "8080",

pkg/provider/traefik/internal.go

@@ -91,15 +91,27 @@ func (i *Provider) createConfiguration(ctx context.Context) *dynamic.Configurati
 }
 
 func (i *Provider) acme(cfg *dynamic.Configuration) {
-	var eps []string
+	allowACMEByPass := map[string]bool{}
+	for name, ep := range i.staticCfg.EntryPoints {
+		allowACMEByPass[name] = ep.AllowACMEByPass
+	}
 
+	var eps []string
+	var epsByPass []string
 	uniq := map[string]struct{}{}
 	for _, resolver := range i.staticCfg.CertificatesResolvers {
 		if resolver.ACME != nil && resolver.ACME.HTTPChallenge != nil && resolver.ACME.HTTPChallenge.EntryPoint != "" {
-			if _, ok := uniq[resolver.ACME.HTTPChallenge.EntryPoint]; !ok {
+			if _, ok := uniq[resolver.ACME.HTTPChallenge.EntryPoint]; ok {
-				eps = append(eps, resolver.ACME.HTTPChallenge.EntryPoint)
+				continue
-				uniq[resolver.ACME.HTTPChallenge.EntryPoint] = struct{}{}
 			}
+			uniq[resolver.ACME.HTTPChallenge.EntryPoint] = struct{}{}
+
+			if allowByPass, ok := allowACMEByPass[resolver.ACME.HTTPChallenge.EntryPoint]; ok && allowByPass {
+				epsByPass = append(epsByPass, resolver.ACME.HTTPChallenge.EntryPoint)
+				continue
+			}
+
+			eps = append(eps, resolver.ACME.HTTPChallenge.EntryPoint)
 		}
 	}
 
@@ -115,6 +127,17 @@ func (i *Provider) acme(cfg *dynamic.Configuration) {
 		cfg.HTTP.Routers["acme-http"] = rt
 		cfg.HTTP.Services["acme-http"] = &dynamic.Service{}
 	}
+
+	if len(epsByPass) > 0 {
+		rt := &dynamic.Router{
+			Rule:        "PathPrefix(`/.well-known/acme-challenge/`)",
+			EntryPoints: epsByPass,
+			Service:     "acme-http@internal",
+		}
+
+		cfg.HTTP.Routers["acme-http-bypass"] = rt
+		cfg.HTTP.Services["acme-http"] = &dynamic.Service{}
+	}
 }
 
 func (i *Provider) redirection(ctx context.Context, cfg *dynamic.Configuration) {

pkg/redactor/redactor_config_test.go

@@ -777,7 +777,7 @@ func TestDo_staticConfiguration(t *testing.T) {
 	}
 
 	config.Providers.HTTP = &http.Provider{
-		Endpoint:     "Myenpoint",
+		Endpoint:     "Myendpoint",
 		PollInterval: 42,
 		PollTimeout:  42,
 		TLS: &types.ClientTLS{

pkg/server/router/router_test.go

@@ -858,7 +858,7 @@ func BenchmarkService(b *testing.B) {
 			LoadBalancer: &dynamic.ServersLoadBalancer{
 				Servers: []dynamic.Server{
 					{
-						URL: "tchouck",
+						URL: "tchouk",
 					},
 				},
 			},

pkg/server/router/tcp/router.go

@@ -21,6 +21,8 @@ const defaultBufSize = 4096
 
 // Router is a TCP router.
 type Router struct {
+	acmeTLSPassthrough bool
+
 	// Contains TCP routes.
 	muxerTCP tcpmuxer.Muxer
 	// Contains TCP TLS routes.
@@ -164,7 +166,7 @@ func (r *Router) ServeTCP(conn tcp.WriteCloser) {
 	}
 
 	// Handling ACME-TLS/1 challenges.
-	if slices.Contains(hello.protos, tlsalpn01.ACMETLS1Protocol) {
+	if !r.acmeTLSPassthrough && slices.Contains(hello.protos, tlsalpn01.ACMETLS1Protocol) {
 		r.acmeTLSALPNHandler().ServeTCP(r.GetConn(conn, hello.peeked))
 		return
 	}
@@ -317,6 +319,10 @@ func (r *Router) SetHTTPSHandler(handler http.Handler, config *tls.Config) {
 	r.httpsTLSConfig = config
 }
 
+func (r *Router) EnableACMETLSPassthrough() {
+	r.acmeTLSPassthrough = true
+}
+
 // Conn is a connection proxy that handles Peeked bytes.
 type Conn struct {
 	// Peeked are the bytes that have been read from Conn for the purposes of route matching,

pkg/server/router/tcp/router_test.go

@@ -215,6 +215,7 @@ func Test_Routing(t *testing.T) {
 		desc                    string
 		routers                 []applyRouter
 		checks                  []checkCase
+		allowACMETLSPassthrough bool
 	}{
 		{
 			desc:    "No routers",
@@ -271,6 +272,18 @@ func Test_Routing(t *testing.T) {
 				},
 			},
 		},
+		{
+			desc:                    "TCP TLS passthrough catches ACME TLS",
+			allowACMETLSPassthrough: true,
+			routers:                 []applyRouter{routerTCPTLSCatchAllPassthrough},
+			checks: []checkCase{
+				{
+					desc:          "ACME TLS Challenge",
+					checkRouter:   checkACMETLS,
+					expectedError: "tls: first record does not look like a TLS handshake",
+				},
+			},
+		},
 		{
 			desc:    "Single TCP CatchAll router",
 			routers: []applyRouter{routerTCPCatchAll},
@@ -596,6 +609,10 @@ func Test_Routing(t *testing.T) {
 			router, err := manager.buildEntryPointHandler(context.Background(), dynConf.TCPRouters, dynConf.Routers, nil, nil)
 			require.NoError(t, err)
 
+			if test.allowACMETLSPassthrough {
+				router.EnableACMETLSPassthrough()
+			}
+
 			epListener, err := net.Listen("tcp", "127.0.0.1:0")
 			require.NoError(t, err)
 
@@ -717,7 +734,7 @@ func routerTCPTLSCatchAll(conf *runtime.Configuration) {
 	}
 }
 
-// routerTCPTLSCatchAllPassthrough a TCP TLS CatchAll Passthrough - HostSNI(`*`) router with TLS 1.0 config.
+// routerTCPTLSCatchAllPassthrough a TCP TLS CatchAll Passthrough - HostSNI(`*`) router with TLS 1.2 config.
 func routerTCPTLSCatchAllPassthrough(conf *runtime.Configuration) {
 	conf.TCPRouters["tcp-tls-catchall-passthrough"] = &runtime.TCPRouterInfo{
 		TCPRouter: &dynamic.TCPRouter{

pkg/server/routerfactory.go

@@ -23,6 +23,7 @@ import (
 type RouterFactory struct {
 	entryPointsTCP  []string
 	entryPointsUDP  []string
+	allowACMEByPass map[string]bool
 
 	managerFactory *service.ManagerFactory
 
@@ -40,9 +41,20 @@ type RouterFactory struct {
 func NewRouterFactory(staticConfiguration static.Configuration, managerFactory *service.ManagerFactory, tlsManager *tls.Manager,
 	observabilityMgr *middleware.ObservabilityMgr, pluginBuilder middleware.PluginsBuilder, dialerManager *tcp.DialerManager,
 ) *RouterFactory {
+	handlesTLSChallenge := false
+	for _, resolver := range staticConfiguration.CertificatesResolvers {
+		if resolver.ACME.TLSChallenge != nil {
+			handlesTLSChallenge = true
+			break
+		}
+	}
+
+	allowACMEByPass := map[string]bool{}
 	var entryPointsTCP, entryPointsUDP []string
-	for name, cfg := range staticConfiguration.EntryPoints {
+	for name, ep := range staticConfiguration.EntryPoints {
-		protocol, err := cfg.GetProtocol()
+		allowACMEByPass[name] = ep.AllowACMEByPass || !handlesTLSChallenge
+
+		protocol, err := ep.GetProtocol()
 		if err != nil {
 			// Should never happen because Traefik should not start if protocol is invalid.
 			log.Error().Err(err).Msg("Invalid protocol")
@@ -63,6 +75,7 @@ func NewRouterFactory(staticConfiguration static.Configuration, managerFactory *
 		tlsManager:       tlsManager,
 		pluginBuilder:    pluginBuilder,
 		dialerManager:    dialerManager,
+		allowACMEByPass:  allowACMEByPass,
 	}
 }
 
@@ -95,6 +108,12 @@ func (f *RouterFactory) CreateRouters(rtConf *runtime.Configuration) (map[string
 	rtTCPManager := tcprouter.NewManager(rtConf, svcTCPManager, middlewaresTCPBuilder, handlersNonTLS, handlersTLS, f.tlsManager)
 	routersTCP := rtTCPManager.BuildHandlers(ctx, f.entryPointsTCP)
 
+	for ep, r := range routersTCP {
+		if allowACMEByPass, ok := f.allowACMEByPass[ep]; ok && allowACMEByPass {
+			r.EnableACMETLSPassthrough()
+		}
+	}
+
 	// UDP
 	svcUDPManager := udpsvc.NewManager(rtConf)
 	rtUDPManager := udprouter.NewManager(rtConf, svcUDPManager)

pkg/server/server_entrypoint_tcp.go

@@ -185,7 +185,10 @@ func NewTCPEntryPoint(ctx context.Context, name string, config *static.EntryPoin
 		return nil, fmt.Errorf("error preparing server: %w", err)
 	}
 
-	rt := &tcprouter.Router{}
+	rt, err := tcprouter.NewRouter()
+	if err != nil {
+		return nil, fmt.Errorf("error preparing tcp router: %w", err)
+	}
 
 	reqDecorator := requestdecorator.New(hostResolverConfig)
 
@@ -607,6 +610,7 @@ func createHTTPServer(ctx context.Context, ln net.Listener, configuration *stati
 	handler, err = forwardedheaders.NewXForwarded(
 		configuration.ForwardedHeaders.Insecure,
 		configuration.ForwardedHeaders.TrustedIPs,
+		configuration.ForwardedHeaders.Connection,
 		next)
 	if err != nil {
 		return nil, err

pkg/server/server_entrypoint_tcp_test.go

@@ -20,7 +20,9 @@ import (
 )
 
 func TestShutdownHijacked(t *testing.T) {
-	router := &tcprouter.Router{}
+	router, err := tcprouter.NewRouter()
+	require.NoError(t, err)
+
 	router.SetHTTPHandler(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 		conn, _, err := rw.(http.Hijacker).Hijack()
 		require.NoError(t, err)
@@ -34,7 +36,9 @@ func TestShutdownHijacked(t *testing.T) {
 }
 
 func TestShutdownHTTP(t *testing.T) {
-	router := &tcprouter.Router{}
+	router, err := tcprouter.NewRouter()
+	require.NoError(t, err)
+
 	router.SetHTTPHandler(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 		rw.WriteHeader(http.StatusOK)
 		time.Sleep(time.Second)
@@ -167,7 +171,9 @@ func TestReadTimeoutWithoutFirstByte(t *testing.T) {
 	}, nil, nil)
 	require.NoError(t, err)
 
-	router := &tcprouter.Router{}
+	router, err := tcprouter.NewRouter()
+	require.NoError(t, err)
+
 	router.SetHTTPHandler(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 		rw.WriteHeader(http.StatusOK)
 	}))
@@ -204,7 +210,9 @@ func TestReadTimeoutWithFirstByte(t *testing.T) {
 	}, nil, nil)
 	require.NoError(t, err)
 
-	router := &tcprouter.Router{}
+	router, err := tcprouter.NewRouter()
+	require.NoError(t, err)
+
 	router.SetHTTPHandler(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 		rw.WriteHeader(http.StatusOK)
 	}))
@@ -244,7 +252,9 @@ func TestKeepAliveMaxRequests(t *testing.T) {
 	}, nil, nil)
 	require.NoError(t, err)
 
-	router := &tcprouter.Router{}
+	router, err := tcprouter.NewRouter()
+	require.NoError(t, err)
+
 	router.SetHTTPHandler(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 		rw.WriteHeader(http.StatusOK)
 	}))
@@ -290,7 +300,9 @@ func TestKeepAliveMaxTime(t *testing.T) {
 	}, nil, nil)
 	require.NoError(t, err)
 
-	router := &tcprouter.Router{}
+	router, err := tcprouter.NewRouter()
+	require.NoError(t, err)
+
 	router.SetHTTPHandler(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 		rw.WriteHeader(http.StatusOK)
 	}))

pkg/tls/certificate_store_test.go

@@ -47,7 +47,7 @@ func TestGetBestCertificate(t *testing.T) {
 			expectedCert:  "*.snitest.com",
 		},
 		{
-			desc:          "Best Match with dynamic wildcard only, case insensitive",
+			desc:          "Best Match with dynamic wildcard only, case-insensitive",
 			domainToCheck: "bar.www.snitest.com",
 			dynamicCert:   "*.www.snitest.com",
 			expectedCert:  "*.www.snitest.com",

pkg/types/domain_test.go

@@ -137,7 +137,7 @@ func TestMatchDomain(t *testing.T) {
 			expected:   true,
 		},
 		{
-			desc:       "dot replaced by a cahr",
+			desc:       "dot replaced by a char",
 			certDomain: "sub.sub.traefik.wtf",
 			domain:     "sub.sub.traefikiwtf",
 			expected:   false,

webui/src/components/_commons/NavBar.vue

@@ -129,7 +129,7 @@
                       align="left"
                       icon="eva-github-outline"
                       no-caps
-                      label="Github repository"
+                      label="GitHub repository"
                       class="btn-submenu full-width"
                     />
                   </q-item>