diff --git a/logback-core/src/main/java/ch/qos/logback/core/AppenderBase.java b/logback-core/src/main/java/ch/qos/logback/core/AppenderBase.java
index 9733b34..7b3a7f8 100644
--- a/logback-core/src/main/java/ch/qos/logback/core/AppenderBase.java
+++ b/logback-core/src/main/java/ch/qos/logback/core/AppenderBase.java
@@ -23,10 +23,10 @@ import ch.qos.logback.core.status.WarnStatus;
 
 /**
  * Sets a skeleton implementation for appenders.
- * 
+ *
  * <p> For more information about this appender, please refer to the online
  * manual at http://logback.qos.ch/manual/appenders.html#AppenderBase
- * 
+ *
  * @author Ceki G&uuml;lc&uuml;
  */
 abstract public class AppenderBase<E> extends ContextAwareBase implements
@@ -41,6 +41,12 @@ abstract public class AppenderBase<E> extends ContextAwareBase implements
   private boolean guard = false;
 
   /**
+   * Normally exceptions are internally logged and then ignored. Setting this to
+   * false will cause the exception to percolate to the application.
+   */
+  protected boolean exceptionMask = true;
+
+  /**
    * Appenders are named.
    */
   protected String name;
@@ -88,6 +94,9 @@ abstract public class AppenderBase<E> extends ContextAwareBase implements
       if (exceptionCount++ < ALLOWED_REPEATS) {
         addError("Appender [" + name + "] failed to append.", e);
       }
+      if (!exceptionMask) {
+        throw new LogbackException("Exception detected in " + this.getClass().getName(), e);
+      }
     } finally {
       guard = false;
     }
@@ -95,6 +104,14 @@ abstract public class AppenderBase<E> extends ContextAwareBase implements
 
   abstract protected void append(E eventObject);
 
+  public void setExceptionMask(boolean mask) {
+    exceptionMask = mask;
+  }
+
+  public boolean isExceptionMask() {
+    return exceptionMask;
+  }
+
   /**
    * Set the name of this appender.
    */
diff --git a/logback-core/src/main/java/ch/qos/logback/core/UnsynchronizedAppenderBase.java b/logback-core/src/main/java/ch/qos/logback/core/UnsynchronizedAppenderBase.java
index 64a0d20..600d1f3 100644
--- a/logback-core/src/main/java/ch/qos/logback/core/UnsynchronizedAppenderBase.java
+++ b/logback-core/src/main/java/ch/qos/logback/core/UnsynchronizedAppenderBase.java
@@ -22,9 +22,9 @@ import ch.qos.logback.core.spi.FilterReply;
 import ch.qos.logback.core.status.WarnStatus;
 
 /**
- * Similar to AppenderBase except that derived appenders need to handle 
+ * Similar to AppenderBase except that derived appenders need to handle
  * thread synchronization on their own.
- * 
+ *
  * @author Ceki G&uuml;lc&uuml;
  * @author Ralph Goers
  */
@@ -33,6 +33,12 @@ abstract public class UnsynchronizedAppenderBase<E> extends ContextAwareBase imp
 
   protected boolean started = false;
 
+  /**
+   * Normally exceptions are internally logged and then ignored. Setting this to
+   * false will cause the exception to percolate to the application.
+   */
+  protected boolean exceptionMask = true;
+
   // using a ThreadLocal instead of a boolean add 75 nanoseconds per
   // doAppend invocation. This is tolerable as doAppend takes at least a few microseconds
   // on a real appender
@@ -94,6 +100,9 @@ abstract public class UnsynchronizedAppenderBase<E> extends ContextAwareBase imp
       if (exceptionCount++ < ALLOWED_REPEATS) {
         addError("Appender [" + name + "] failed to append.", e);
       }
+      if (!exceptionMask) {
+        throw new LogbackException("Exception detected in " + this.getClass().getName(), e);
+      }
     } finally {
       guard.set(false);
     }
@@ -101,6 +110,14 @@ abstract public class UnsynchronizedAppenderBase<E> extends ContextAwareBase imp
 
   abstract protected void append(E eventObject);
 
+  public void setExceptionMask(boolean mask) {
+    exceptionMask = mask;
+  }
+
+  public boolean isExceptionMask() {
+    return exceptionMask;
+  }
+
   /**
    * Set the name of this appender.
    */
@@ -136,7 +153,7 @@ abstract public class UnsynchronizedAppenderBase<E> extends ContextAwareBase imp
     return fai.getCopyOfAttachedFiltersList();
   }
 
-  
+
   public FilterReply getFilterChainDecision(E event) {
     return fai.getFilterChainDecision(event);
   }
diff --git a/logback-core/src/test/java/ch/qos/logback/core/appender/AppenderExceptionTest.java b/logback-core/src/test/java/ch/qos/logback/core/appender/AppenderExceptionTest.java
index 696d18d..63928fa 100644
--- a/logback-core/src/test/java/ch/qos/logback/core/appender/AppenderExceptionTest.java
+++ b/logback-core/src/test/java/ch/qos/logback/core/appender/AppenderExceptionTest.java
@@ -22,6 +22,7 @@ import static org.junit.Assert.fail;
 
 import ch.qos.logback.core.Appender;
 import ch.qos.logback.core.AppenderBase;
+import ch.qos.logback.core.UnsynchronizedAppenderBase;
 import org.junit.Test;
 
 /**
@@ -32,33 +33,37 @@ public class AppenderExceptionTest {
     @Test
     public void testAppenderBaseException() {
         MockAppender a = new MockAppender();
+        a.start();
         try {
             a.doAppend("Test");
         } catch (Exception ex) {
             fail("Unexpected exception caught");
         }
-        a.setExceptionMask(true);
+        a.setExceptionMask(false);
         try {
             a.doAppend("Test");
             fail("Expected exception not thrown");
         } catch (Exception ex) {
         }
+        a.stop();
     }
 
     @Test
     public void testUnsynchronizedAppenderBaseException() {
-        MockAppender a = new MockAppender();
+        MockUnsynchronizedAppender a = new MockUnsynchronizedAppender();
+        a.start();
         try {
             a.doAppend("Test");
         } catch (Exception ex) {
             fail("Unexpected exception caught");
         }
-        a.setExceptionMask(true);
+        a.setExceptionMask(false);
         try {
             a.doAppend("Test");
             fail("Expected exception not thrown");
         } catch (Exception ex) {
         }
+        a.stop();
     }
 
     public class MockAppender extends AppenderBase<Object> {
@@ -68,10 +73,10 @@ public class AppenderExceptionTest {
         }
     }
 
-    public class MockAppender extends AppenderBase<Object> {
+    public class MockUnsynchronizedAppender extends UnsynchronizedAppenderBase<Object> {
         @Override
         protected void append(Object eventObject) {
             throw new RuntimeException("Test");
         }
-    }    
+    }
 }