diff --git a/ldap/src/main/java/org/springframework/security/config/ldap/ContextSourceSettingPostProcessor.java b/ldap/src/main/java/org/springframework/security/config/ldap/ContextSourceSettingPostProcessor.java
new file mode 100644
index 0000000000..9211b354a0
--- /dev/null
+++ b/ldap/src/main/java/org/springframework/security/config/ldap/ContextSourceSettingPostProcessor.java
@@ -0,0 +1,52 @@
+package org.springframework.security.config.ldap;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.core.Ordered;
+import org.springframework.ldap.core.support.BaseLdapPathContextSource;
+import org.springframework.security.config.BeanIds;
+import org.springframework.security.config.Elements;
+import org.springframework.security.config.SecurityConfigurationException;
+
+/**
+ * Checks for the presence of a ContextSource instance. Also supplies the standard reference to any
+ * unconfigured <ldap-authentication-provider> or <ldap-user-service> beans. This is
+ * necessary in cases where the user has given the server a specific Id, but hasn't used
+ * the server-ref attribute to link this to the other ldap definitions. See SEC-799.
+ *
+ * @author Luke Taylor
+ * @version $Id$
+ * @since 2.5
+ */
+public class ContextSourceSettingPostProcessor implements BeanFactoryPostProcessor, Ordered {
+    /** If set to true, a bean parser has indicated that the default context source name needs to be set */
+    private boolean defaultNameRequired;
+
+    public void postProcessBeanFactory(ConfigurableListableBeanFactory bf) throws BeansException {
+        String[] sources = bf.getBeanNamesForType(BaseLdapPathContextSource.class);
+
+        if (sources.length == 0) {
+            throw new SecurityConfigurationException("No BaseLdapPathContextSource instances found. Have you " +
+                    "added an <" + Elements.LDAP_SERVER + " /> element to your application context?");
+        }
+
+        if (!bf.containsBean(BeanIds.CONTEXT_SOURCE) && defaultNameRequired) {
+            if (sources.length > 1) {
+                throw new SecurityConfigurationException("More than one BaseLdapPathContextSource instance found. " +
+                        "Please specify a specific server id using the 'server-ref' attribute when configuring your <" +
+                        Elements.LDAP_PROVIDER + "> " + "or <" + Elements.LDAP_USER_SERVICE + ">.");
+            }
+
+            bf.registerAlias(sources[0], BeanIds.CONTEXT_SOURCE);
+        }
+    }
+
+    public void setDefaultNameRequired(boolean defaultNameRequired) {
+        this.defaultNameRequired = defaultNameRequired;
+    }
+
+    public int getOrder() {
+        return LOWEST_PRECEDENCE;
+    }
+}