diff --git a/hsarback/src/de/hsadmin/mods/dom/Domain.java b/hsarback/src/de/hsadmin/mods/dom/Domain.java
index 7fa8bd2..a6d0575 100644
--- a/hsarback/src/de/hsadmin/mods/dom/Domain.java
+++ b/hsarback/src/de/hsadmin/mods/dom/Domain.java
@@ -196,8 +196,11 @@ public class Domain extends AbstractEntity {
 		StringBuffer aliases = new StringBuffer();
 		for (String sub : subs) {
 			aliases.append(' ');
-			aliases.append(sub.trim());
-			aliases.append('.');
+			final String trimmed = sub.trim();
+			if (trimmed != null && !trimmed.isEmpty()) {
+				aliases.append(trimmed);
+				aliases.append('.');
+			}
 			aliases.append(name);
 		}
 		return aliases.toString();