diff --git a/src/cloud/common/CloudAuth.rb b/src/cloud/common/CloudAuth.rb
index b69934dd81..3177e95247 100644
--- a/src/cloud/common/CloudAuth.rb
+++ b/src/cloud/common/CloudAuth.rb
@@ -33,7 +33,8 @@ class CloudAuth
 
     # Default interval for timestamps. Tokens will be generated using the same
     # timestamp for this interval of time.
-    EXPIRE_DELTA = 36000
+    # THIS VALUE CANNOT BE LOWER THAN EXPIRE_MARGIN
+    EXPIRE_DELTA = 1800
 
     # Tokens will be generated if time > EXPIRE_TIME - EXPIRE_MARGIN
     EXPIRE_MARGIN = 300
@@ -44,11 +45,7 @@ class CloudAuth
     def initialize(conf)
         @conf = conf
 
-        # @token_expiration_delta:  Number of seconds that will be used
-        #   the same timestamp for the token generation
-        # @token_expiration_time:   Current timestamp to be used in tokens.
-        @token_expiration_delta = @conf[:token_expiration_delta] || EXPIRE_DELTA
-        @token_expiration_time = Time.now.to_i + @token_expiration_delta
+        @token_expiration_time = Time.now.to_i + EXPIRE_DELTA
 
         if AUTH_MODULES.include?(@conf[:auth])
             require 'CloudAuth/' + AUTH_MODULES[@conf[:auth]]
@@ -90,13 +87,24 @@ class CloudAuth
         end
     end
 
+    def auth(env, params={})
+        username = do_auth(env, params)
+
+        if username.nil?
+            update_userpool_cache
+            do_auth(env, params)
+        else
+            username
+        end
+    end
+
     protected
 
     def expiration_time
         time_now = Time.now.to_i
 
         if time_now > @token_expiration_time - EXPIRE_MARGIN
-            @token_expiration_time = time_now + @token_expiration_delta
+            @token_expiration_time = time_now + EXPIRE_DELTA
             update_userpool_cache
         end
 
diff --git a/src/cloud/common/CloudAuth/EC2CloudAuth.rb b/src/cloud/common/CloudAuth/EC2CloudAuth.rb
index e60f653648..bad85c6cac 100644
--- a/src/cloud/common/CloudAuth/EC2CloudAuth.rb
+++ b/src/cloud/common/CloudAuth/EC2CloudAuth.rb
@@ -15,7 +15,7 @@
 #--------------------------------------------------------------------------- #
 
 module EC2CloudAuth
-    def auth(env, params={})
+    def do_auth(env, params={})
         username = params['AWSAccessKeyId']
         one_pass = get_password(username)
         return nil unless one_pass
diff --git a/src/cloud/common/CloudAuth/OCCICloudAuth.rb b/src/cloud/common/CloudAuth/OCCICloudAuth.rb
index e6f80c4f67..4fac9905d9 100644
--- a/src/cloud/common/CloudAuth/OCCICloudAuth.rb
+++ b/src/cloud/common/CloudAuth/OCCICloudAuth.rb
@@ -15,7 +15,7 @@
 #--------------------------------------------------------------------------- #
 
 module OCCICloudAuth
-    def auth(env, params={})
+    def do_auth(env, params={})
         auth = Rack::Auth::Basic::Request.new(env)
 
         if auth.provided? && auth.basic?
@@ -28,6 +28,6 @@ module OCCICloudAuth
             end
         end
 
-        return nil 
-    end 
+        return nil
+    end
 end
\ No newline at end of file
diff --git a/src/cloud/common/CloudAuth/SunstoneCloudAuth.rb b/src/cloud/common/CloudAuth/SunstoneCloudAuth.rb
index 9fa855b1d0..69fcb42db5 100644
--- a/src/cloud/common/CloudAuth/SunstoneCloudAuth.rb
+++ b/src/cloud/common/CloudAuth/SunstoneCloudAuth.rb
@@ -15,7 +15,7 @@
 #--------------------------------------------------------------------------- #
 
 module SunstoneCloudAuth
-    def auth(env, params={})
+    def do_auth(env, params={})
         auth = Rack::Auth::Basic::Request.new(env)
 
         if auth.provided? && auth.basic?
@@ -28,6 +28,6 @@ module SunstoneCloudAuth
             end
         end
 
-        return nil 
-    end 
+        return nil
+    end
 end
\ No newline at end of file
diff --git a/src/cloud/common/CloudAuth/X509CloudAuth.rb b/src/cloud/common/CloudAuth/X509CloudAuth.rb
index 60f52a0562..5e8613eef7 100644
--- a/src/cloud/common/CloudAuth/X509CloudAuth.rb
+++ b/src/cloud/common/CloudAuth/X509CloudAuth.rb
@@ -15,7 +15,7 @@
 #--------------------------------------------------------------------------- #
 
 module X509CloudAuth
-    def auth(env, params={})
+    def do_auth(env, params={})
         # For https, the web service should be set to include the user cert in the environment.
         cert_line   = env['HTTP_SSL_CLIENT_CERT']
         cert_line   = nil if cert_line == '(null)' # For Apache mod_ssl
diff --git a/src/cloud/ec2/etc/econe.conf b/src/cloud/ec2/etc/econe.conf
index 2f681596c7..9ef6851f2b 100644
--- a/src/cloud/ec2/etc/econe.conf
+++ b/src/cloud/ec2/etc/econe.conf
@@ -33,8 +33,6 @@
 #   cipher, for symmetric cipher encryption of tokens
 #   x509, for x509 certificate encryption of tokens
 :core_auth: cipher
-# Life-time in seconds for token renewal (that used to handle OpenNebula auths)
-:token_expiration_delta: 1800
 
 # VM types allowed and its template file (inside templates directory)
 :instance_types:
diff --git a/src/cloud/occi/etc/occi-server.conf b/src/cloud/occi/etc/occi-server.conf
index f81fa1924a..6304fa24f5 100644
--- a/src/cloud/occi/etc/occi-server.conf
+++ b/src/cloud/occi/etc/occi-server.conf
@@ -36,8 +36,6 @@
 #   cipher, for symmetric cipher encryption of tokens
 #   x509, for x509 certificate encryption of tokens
 :core_auth: cipher
-# Life-time in seconds for token renewal (that used to handle OpenNebula auths)
-:token_expiration_delta: 1800
 
 # VM types allowed and its template file (inside templates directory)
 :instance_types:
diff --git a/src/sunstone/etc/sunstone-server.conf b/src/sunstone/etc/sunstone-server.conf
index 2311501782..4391ca8a5f 100644
--- a/src/sunstone/etc/sunstone-server.conf
+++ b/src/sunstone/etc/sunstone-server.conf
@@ -14,9 +14,7 @@
 #   cipher, for symmetric cipher encryption of tokens
 #   x509, for x509 certificate encryption of tokens
 :core_auth: cipher
-# Life-time in seconds for token renewal (that used to handle OpenNebula auths)
-:token_expiration_delta: 1800
-	
+
 # VNC Configuration
 :vnc_proxy_base_port: 29876
-:novnc_path: 
+:novnc_path: