fix: drop host port to compare with SNI.

integration/https_test.go

@@ -1150,6 +1150,34 @@ func (s *HTTPSSuite) TestWithDomainFronting(c *check.C) {
 			expectedContent:    "server1",
 			expectedStatusCode: http.StatusOK,
 		},
+		{
+			desc:               "Simple case with port in the Host Header",
+			hostHeader:         "site3.www.snitest.com:4443",
+			serverName:         "site3.www.snitest.com",
+			expectedContent:    "server3",
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			desc:               "Spaces after the host header",
+			hostHeader:         "site3.www.snitest.com ",
+			serverName:         "site3.www.snitest.com",
+			expectedContent:    "server3",
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			desc:               "Spaces after the servername",
+			hostHeader:         "site3.www.snitest.com",
+			serverName:         "site3.www.snitest.com ",
+			expectedContent:    "server3",
+			expectedStatusCode: http.StatusOK,
+		},
+		{
+			desc:               "Spaces after the servername and host header",
+			hostHeader:         "site3.www.snitest.com ",
+			serverName:         "site3.www.snitest.com ",
+			expectedContent:    "server3",
+			expectedStatusCode: http.StatusOK,
+		},
 		{
 			desc:               "Domain Fronting with same tlsOptions should follow header",
 			hostHeader:         "site1.www.snitest.com",
@@ -1189,9 +1217,11 @@ func (s *HTTPSSuite) TestWithDomainFronting(c *check.C) {
 
 	for _, test := range testCases {
 		test := test
+
 		req, err := http.NewRequest(http.MethodGet, "https://127.0.0.1:4443", nil)
 		c.Assert(err, checker.IsNil)
 		req.Host = test.hostHeader
+
 		err = try.RequestWithTransport(req, 500*time.Millisecond, &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true, ServerName: test.serverName}}, try.StatusCodeIs(test.expectedStatusCode), try.BodyContains(test.expectedContent))
 		c.Assert(err, checker.IsNil)
 	}

pkg/server/router/tcp/router.go

@@ -5,6 +5,7 @@ import (
 	"crypto/tls"
 	"errors"
 	"fmt"
+	"net"
 	"net/http"
 	"strings"
 
@@ -141,6 +142,7 @@ func (m *Manager) buildEntryPointHandler(ctx context.Context, configs map[string
 					continue
 				}
 
+				// domain is already in lower case thanks to the domain parsing
 				if tlsOptionsForHostSNI[domain] == nil {
 					tlsOptionsForHostSNI[domain] = make(map[string]nameAndConfig)
 				}
@@ -149,27 +151,46 @@ func (m *Manager) buildEntryPointHandler(ctx context.Context, configs map[string
 					TLSConfig:  tlsConf,
 				}
 
-				lowerDomain := strings.ToLower(domain)
+				if _, ok := tlsOptionsForHost[domain]; ok {
-				if _, ok := tlsOptionsForHost[lowerDomain]; ok {
 					// Multiple tlsOptions fallback to default
-					tlsOptionsForHost[lowerDomain] = "default"
+					tlsOptionsForHost[domain] = "default"
 				} else {
-					tlsOptionsForHost[lowerDomain] = routerHTTPConfig.TLS.Options
+					tlsOptionsForHost[domain] = routerHTTPConfig.TLS.Options
 				}
 			}
 		}
 	}
 
 	sniCheck := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
-		if req.TLS != nil && !strings.EqualFold(req.Host, req.TLS.ServerName) {
+		if req.TLS == nil {
-			tlsOptionSNI := findTLSOptionName(tlsOptionsForHost, req.TLS.ServerName)
+			handlerHTTPS.ServeHTTP(rw, req)
-			tlsOptionHeader := findTLSOptionName(tlsOptionsForHost, req.Host)
+			return
+		}
+
+		host, _, err := net.SplitHostPort(req.Host)
+		if err != nil {
+			host = req.Host
+		}
+
+		host = strings.TrimSpace(host)
+		serverName := strings.TrimSpace(req.TLS.ServerName)
+
+		// Domain Fronting
+		if !strings.EqualFold(host, serverName) {
+			tlsOptionSNI := findTLSOptionName(tlsOptionsForHost, serverName)
+			tlsOptionHeader := findTLSOptionName(tlsOptionsForHost, host)
 
 			if tlsOptionHeader != tlsOptionSNI {
+				log.WithoutContext().
+					WithField("host", host).
+					WithField("req.Host", req.Host).
+					WithField("req.TLS.ServerName", req.TLS.ServerName).
+					Debugf("TLS options difference: SNI=%s, Header:%s", tlsOptionSNI, tlsOptionHeader)
 				http.Error(rw, http.StatusText(http.StatusMisdirectedRequest), http.StatusMisdirectedRequest)
 				return
 			}
 		}
+
 		handlerHTTPS.ServeHTTP(rw, req)
 	})
 

pkg/tcp/router.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/containous/traefik/v2/pkg/log"
+	"github.com/containous/traefik/v2/pkg/types"
 )
 
 // Router is a TCP router.
@@ -65,7 +66,7 @@ func (r *Router) ServeTCP(conn WriteCloser) {
 	}
 
 	// FIXME Optimize and test the routing table before helloServerName
-	serverName = strings.ToLower(serverName)
+	serverName = types.CanonicalDomain(serverName)
 	if r.routingTable != nil && serverName != "" {
 		if target, ok := r.routingTable[serverName]; ok {
 			target.ServeTCP(r.GetConn(conn, peeked))