diff --git a/src/main/java/de/hsfulda/informatik/LdapSync.java b/src/main/java/de/hsfulda/informatik/LdapSync.java
index fc2f8d7..d46b44e 100644
--- a/src/main/java/de/hsfulda/informatik/LdapSync.java
+++ b/src/main/java/de/hsfulda/informatik/LdapSync.java
@@ -27,6 +27,7 @@ public class LdapSync {
     private final Properties properties = new Properties();
     private final static Pattern legacyPattern = Pattern.compile("^fd([a-z][a-z])?([0-9]*?)$");
     private final static Pattern newPattern = Pattern.compile("^fd([0-9][0-9][0-9][0-9][0-9][0-9][0-9])$");
+    private final static Pattern newGuestPattern = Pattern.compile("^fdg([0-9][0-9][0-9][0-9][0-9])$");
     private Map<String, Integer> userDefinedMappings = Collections.emptyMap();
 
     public LdapSync() throws IOException, LDAPException, GeneralSecurityException {
@@ -157,6 +158,13 @@ public class LdapSync {
             return 270000000 + Integer.parseInt(x.group(1));
         }
 
+        final Matcher y = newGuestPattern.matcher(cn);
+
+        if (y.find()) {
+            return 300000000 + Integer.parseInt(y.group(1));
+        }
+
+
         final Matcher m = legacyPattern.matcher(cn);
 
         if (m.find()) {
diff --git a/src/test/java/de/hsfulda/informatik/LdapSyncTest.java b/src/test/java/de/hsfulda/informatik/LdapSyncTest.java
index 3f7ee27..52ce44a 100644
--- a/src/test/java/de/hsfulda/informatik/LdapSyncTest.java
+++ b/src/test/java/de/hsfulda/informatik/LdapSyncTest.java
@@ -122,6 +122,8 @@ public class LdapSyncTest {
         assertEquals(10149999, (int) LdapSync.computeUid("fdaa9999", mappings));
         assertEquals(262641000, (int) LdapSync.computeUid("fdzz1000", mappings));
         assertEquals(262649999, (int) LdapSync.computeUid("fdzz9999", mappings));
+        assertEquals(300000000, (int) LdapSync.computeUid("fdg00000", mappings));
+        assertEquals(300099999, (int) LdapSync.computeUid("fdg99999", mappings));
 
         mappings = LdapSync.parseUserDefinedMappings("aaabbb");
         assertEquals(0, mappings.size());