diff --git a/configuration/validator/authentication.go b/configuration/validator/authentication.go
index b3a8a8c2..c81f328b 100644
--- a/configuration/validator/authentication.go
+++ b/configuration/validator/authentication.go
@@ -2,20 +2,42 @@ package validator
 
 import (
 	"errors"
+	"fmt"
+	"strings"
 
 	"github.com/clems4ever/authelia/configuration/schema"
 )
 
+var ldapProtocolPrefix = "ldap://"
+
 func validateFileAuthenticationBackend(configuration *schema.FileAuthenticationBackendConfiguration, validator *schema.StructValidator) {
 	if configuration.Path == "" {
 		validator.Push(errors.New("Please provide a `path` for the users database in `authentication_backend`"))
 	}
 }
 
+func validateLdapURL(url string, validator *schema.StructValidator) string {
+	if strings.HasPrefix(url, ldapProtocolPrefix) {
+		url = url[len(ldapProtocolPrefix):]
+	}
+
+	portColons := strings.Index(url, ":")
+
+	// if no port is provided, we provide the default LDAP port
+	// TODO(c.michaud): support LDAP over TLS.
+	if portColons == -1 {
+		url = url + ":389"
+	}
+	return url
+}
+
 func validateLdapAuthenticationBackend(configuration *schema.LDAPAuthenticationBackendConfiguration, validator *schema.StructValidator) {
 	if configuration.URL == "" {
 		validator.Push(errors.New("Please provide a URL to the LDAP server"))
+	} else {
+		configuration.URL = validateLdapURL(configuration.URL, validator)
 	}
+	fmt.Println(configuration.URL)
 
 	if configuration.User == "" {
 		validator.Push(errors.New("Please provide a user name to connect to the LDAP server"))
@@ -30,11 +52,11 @@ func validateLdapAuthenticationBackend(configuration *schema.LDAPAuthenticationB
 	}
 
 	if configuration.UsersFilter == "" {
-		configuration.UsersFilter = "cn={0}"
+		configuration.UsersFilter = "(cn={0})"
 	}
 
 	if configuration.GroupsFilter == "" {
-		configuration.GroupsFilter = "member={dn}"
+		configuration.GroupsFilter = "(member={dn})"
 	}
 
 	if configuration.GroupNameAttribute == "" {
diff --git a/test/suites/high-availability/config.yml b/test/suites/high-availability/config.yml
index 11b7a621..e975e33b 100644
--- a/test/suites/high-availability/config.yml
+++ b/test/suites/high-availability/config.yml
@@ -44,7 +44,7 @@ authentication_backend:
   # production.
   ldap:
     # The url of the ldap server
-    url: 127.0.0.1:389
+    url: ldap://127.0.0.1
 
     # The base dn for every entries
     base_dn: dc=example,dc=com