diff --git a/services/auth/reverseproxy.go b/services/auth/reverseproxy.go
index 3e44d8b8639ca..60fcb642b1262 100644
--- a/services/auth/reverseproxy.go
+++ b/services/auth/reverseproxy.go
@@ -6,9 +6,11 @@
 package auth
 
 import (
+	"fmt"
 	"net/http"
 	"strings"
 
+	"code.gitea.io/gitea/models/db"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -55,32 +57,70 @@ func (r *ReverseProxy) Name() string {
 // the revese proxy.
 // If a username is available in the "setting.ReverseProxyAuthUser" header an existing
 // user object is returned (populated with username or email found in header).
-// Returns nil if header is empty.
+// Returns nil if header is empty or internal API is being called.
 func (r *ReverseProxy) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) *user_model.User {
+
+	// Internal API should not use this auth method.
+	if middleware.IsInternalPath(req) {
+		return nil
+	}
+
+	var user *user_model.User = nil
+
 	username := r.getUserName(req)
 	if len(username) == 0 {
 		return nil
 	}
 	log.Trace("ReverseProxy Authorization: Found username: %s", username)
 
-	user, err := user_model.GetUserByName(username)
-	if err != nil {
-		if !user_model.IsErrUserNotExist(err) || !r.isAutoRegisterAllowed() {
-			log.Error("GetUserByName: %v", err)
+	var err error
+
+	if r.isAutoRegisterAllowed() {
+		// Use auto registration from reverse proxy if ENABLE_REVERSE_PROXY_AUTO_REGISTRATION enabled.
+		if user, err = user_model.GetUserByName(username); err != nil {
+			if user_model.IsErrUserNotExist(err) && r.isAutoRegisterAllowed() {
+				if user = r.newUser(req); user == nil {
+					return nil
+				}
+			} else {
+				log.Error("GetUserByName: %v", err)
+				return nil
+			}
+		}
+	} else {
+		// Use auto registration from other backends if ENABLE_REVERSE_PROXY_AUTO_REGISTRATION not enabled.
+		if user, _, err = UserSignIn(username, ""); err != nil {
+			if !user_model.IsErrUserNotExist(err) {
+				log.Error("UserSignIn: %v", err)
+			}
 			return nil
 		}
-		user = r.newUser(req)
 	}
 
 	// Make sure requests to API paths, attachment downloads, git and LFS do not create a new session
 	if !middleware.IsAPIPath(req) && !isAttachmentDownload(req) && !isGitRawReleaseOrLFSPath(req) {
 		if sess != nil && (sess.Get("uid") == nil || sess.Get("uid").(int64) != user.ID) {
+
+			// Register last login.
+			user.SetLastLogin()
+
+			if err = user_model.UpdateUserCols(db.DefaultContext, user, "last_login_unix"); err != nil {
+				log.Error(fmt.Sprintf("ReverseProxy Authorization: error updating user last login time [user: %d]", user.ID))
+			}
+
+			// Initialize new session. Will set lang and CSRF cookies.
 			handleSignIn(w, req, sess, user)
+
+			log.Trace("ReverseProxy Authorization: Logged in user %-v", user)
 		}
+
+		// Unfortunatelly we cannot do redirect here (would break git HTTP requests) to
+		// reload page with user locale so first page after login may be displayed in
+		// wrong language. Language handling in SSO mode should be reconsidered
+		// in future gitea versions.
 	}
-	store.GetData()["IsReverseProxy"] = true
 
-	log.Trace("ReverseProxy Authorization: Logged in user %-v", user)
+	store.GetData()["IsReverseProxy"] = true
 	return user
 }
 
diff --git a/services/auth/source/ldap/source_authenticate.go b/services/auth/source/ldap/source_authenticate.go
index 52971bb87e58c..665f1a73d21fd 100644
--- a/services/auth/source/ldap/source_authenticate.go
+++ b/services/auth/source/ldap/source_authenticate.go
@@ -39,6 +39,17 @@ func (source *Source) Authenticate(user *user_model.User, userName, password str
 		}
 		if user != nil && !user.ProhibitLogin {
 			cols := make([]string, 0)
+			fullName := composeFullName(sr.Name, sr.Surname, sr.Username)
+			if user.FullName != fullName {
+				// Update user fullname if changed.
+				user.FullName = fullName
+				cols = append(cols, "full_name")
+			}
+			if !strings.EqualFold(user.Email, sr.Mail) {
+				// Update user e-mail if changed.
+				user.Email = sr.Mail
+				cols = append(cols, "email")
+			}
 			if len(source.AdminFilter) > 0 && user.IsAdmin != sr.IsAdmin {
 				// Change existing admin flag only if AdminFilter option is set
 				user.IsAdmin = sr.IsAdmin
@@ -49,6 +60,11 @@ func (source *Source) Authenticate(user *user_model.User, userName, password str
 				user.IsRestricted = sr.IsRestricted
 				cols = append(cols, "is_restricted")
 			}
+			if !user.IsActive {
+				// User existing in LDAP should be active in application.
+				user.IsActive = true
+				cols = append(cols, "is_active")
+			}
 			if len(cols) > 0 {
 				err = user_model.UpdateUserCols(db.DefaultContext, user, cols...)
 				if err != nil {
diff --git a/services/auth/source/ldap/source_search.go b/services/auth/source/ldap/source_search.go
index 1f1cca270d40a..d7a5a17f50dac 100644
--- a/services/auth/source/ldap/source_search.go
+++ b/services/auth/source/ldap/source_search.go
@@ -13,6 +13,7 @@ import (
 	"strings"
 
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
 
 	"github.com/go-ldap/ldap/v3"
 )
@@ -194,11 +195,23 @@ func checkRestricted(l *ldap.Conn, ls *Source, userDN string) bool {
 
 // SearchEntry : search an LDAP source if an entry (name, passwd) is valid and in the specific filter
 func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResult {
+
 	// See https://tools.ietf.org/search/rfc4513#section-5.1.2
-	if len(passwd) == 0 {
+	// Don't authenticate against LDAP if already authenticated by reverse proxy.
+	if setting.Service.EnableReverseProxyAuth {
+		if directBind {
+			log.Debug("Cannot bind pre-authenticated user %s. BindDN must be used.", name)
+			return nil
+		}
+		if !ls.AttributesInBind {
+			log.Debug("Cannot get attributes for pre-authenticated user %s without --attributes-in-bind.", name)
+			return nil
+		}
+	} else if len(passwd) == 0 {
 		log.Debug("Auth. failed for %s, password cannot be empty", name)
 		return nil
 	}
+
 	l, err := dial(ls)
 	if err != nil {
 		log.Error("LDAP Connect error, %s:%v", ls.Host, err)
@@ -361,8 +374,8 @@ func (ls *Source) SearchEntry(name, passwd string, directBind bool) *SearchResul
 		isRestricted = checkRestricted(l, ls, userDN)
 	}
 
-	if !directBind && ls.AttributesInBind {
-		// binds user (checking password) after looking-up attributes in BindDN context
+	if !directBind && ls.AttributesInBind && !setting.Service.EnableReverseProxyAuth {
+		// Binds user (checking password) after looking-up attributes in BindDN context if not already authenticated.
 		err = bindUser(l, userDN, passwd)
 		if err != nil {
 			return nil