diff --git a/mdx/_rules/check_mdui.xsl b/mdx/_rules/check_mdui.xsl
index 17e14b9..5f989a3 100644
--- a/mdx/_rules/check_mdui.xsl
+++ b/mdx/_rules/check_mdui.xsl
@@ -18,7 +18,6 @@
     xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
     xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
     xmlns:mdui="urn:oasis:names:tc:SAML:metadata:ui"
-    xmlns:mdxURL="xalan://uk.ac.sdss.xalan.md.URLchecker"
     xmlns:set="http://exslt.org/sets"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="urn:oasis:names:tc:SAML:2.0:metadata">
@@ -131,103 +130,6 @@
         </xsl:if>
     </xsl:template>
 
-
-    <!--
-        Section 2.1.5 Element <mdui:Logo>
-    -->
-    <xsl:template match="mdui:Logo">
-        <!--
-            Logos must never include un-encoded line breaks. This makes them invalid
-            URLs, but also causes problems with the Shibboleth CDS.
-        -->
-        <xsl:if test="contains(., '&#10;')">
-            <xsl:call-template name="error">
-                <xsl:with-param name="m">mdui:Logo contains line break</xsl:with-param>
-            </xsl:call-template>
-        </xsl:if>
-
-        <xsl:if test="contains(., '&#xA0;')">
-            <xsl:call-template name="error">
-                <xsl:with-param name="m">mdui:Logo contains non-breaking space</xsl:with-param>
-            </xsl:call-template>
-        </xsl:if>
-
-        <!--
-            Require that the URL starts with https://
-
-            This is a SHOULD in the specification; we treat it as a MUST here.
-
-            Exception: allow data: URIs as well.  The spec is currently
-            ambiguous about this, clarification ticket is here:
-
-            https://tools.oasis-open.org/issues/browse/SECURITY-24
-        -->
-        <xsl:if test="not(starts-with(., 'https://'))">
-            <xsl:if test="not(starts-with(., 'data:'))">
-                <xsl:call-template name="error">
-                    <xsl:with-param name="m">mdui:Logo URL does not start with https://</xsl:with-param>
-                </xsl:call-template>
-            </xsl:if>
-        </xsl:if>
-
-        <!--
-            Check for <mdui:Logo> elements that aren't valid URLs.
-
-            Again, explicitly permit anything starting with 'data:', so that the
-            only validity test we're performing on data: URLs is the "no newline" rule.
-        -->
-        <xsl:if test="mdxURL:invalidURL(.)">
-            <xsl:if test="not(starts-with(., 'data:'))">
-                <xsl:call-template name="error">
-                    <xsl:with-param name="m">
-                        <xsl:text>mdui:</xsl:text>
-                        <xsl:value-of select='local-name()'/>
-                        <xsl:text> '</xsl:text>
-                        <xsl:value-of select="."/>
-                        <xsl:text>' is not a valid URL: </xsl:text>
-                        <xsl:value-of select="mdxURL:whyInvalid(.)"/>
-                    </xsl:with-param>
-                </xsl:call-template>
-            </xsl:if>
-        </xsl:if>
-    </xsl:template>
-
-    <!--
-        Section 2.1.6 Element <mdui:InformationURL>
-
-        Require that the URL is valid.
-    -->
-    <xsl:template match="mdui:InformationURL[mdxURL:invalidURL(.)]">
-        <xsl:call-template name="error">
-            <xsl:with-param name="m">
-                <xsl:text>mdui:</xsl:text>
-                <xsl:value-of select='local-name()'/>
-                <xsl:text> '</xsl:text>
-                <xsl:value-of select="."/>
-                <xsl:text>' is not a valid URL: </xsl:text>
-                <xsl:value-of select="mdxURL:whyInvalid(.)"/>
-            </xsl:with-param>
-        </xsl:call-template>
-    </xsl:template>
-
-    <!--
-        Section 2.1.7 Element <mdui:PrivacyStatementURL>
-
-        Require that the URL is valid.
-    -->
-    <xsl:template match="mdui:PrivacyStatementURL[mdxURL:invalidURL(.)]">
-        <xsl:call-template name="error">
-            <xsl:with-param name="m">
-                <xsl:text>mdui:</xsl:text>
-                <xsl:value-of select='local-name()'/>
-                <xsl:text> '</xsl:text>
-                <xsl:value-of select="."/>
-                <xsl:text>' is not a valid URL: </xsl:text>
-                <xsl:value-of select="mdxURL:whyInvalid(.)"/>
-            </xsl:with-param>
-        </xsl:call-template>
-    </xsl:template>
-
     <!--
         Section 2.2
 
diff --git a/mdx/_rules/check_saml2meta.xsl b/mdx/_rules/check_saml2meta.xsl
index 42b5fad..3a3cda5 100644
--- a/mdx/_rules/check_saml2meta.xsl
+++ b/mdx/_rules/check_saml2meta.xsl
@@ -11,7 +11,6 @@
 -->
 <xsl:stylesheet version="1.0"
     xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
-    xmlns:mdxURL="xalan://uk.ac.sdss.xalan.md.URLchecker"
     xmlns:set="http://exslt.org/sets"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
@@ -66,48 +65,4 @@
         <xsl:apply-templates/>
     </xsl:template>
 
-
-    <!--
-        Check for Location attributes that aren't valid URLs.
-    -->
-    <xsl:template match="md:*[@Location and mdxURL:invalidURL(@Location)]">
-        <xsl:call-template name="error">
-            <xsl:with-param name="m">
-                <xsl:value-of select='local-name()'/>
-                <xsl:text> Location is not a valid URL: </xsl:text>
-                <xsl:value-of select="mdxURL:whyInvalid(@Location)"/>
-            </xsl:with-param>
-        </xsl:call-template>
-    </xsl:template>
-
-
-    <!--
-        Check for ResponseLocation attributes that aren't valid URLs.
-    -->
-    <xsl:template match="md:*[@ResponseLocation and mdxURL:invalidURL(@ResponseLocation)]">
-        <xsl:call-template name="error">
-            <xsl:with-param name="m">
-                <xsl:value-of select='local-name()'/>
-                <xsl:text> ResponseLocation is not a valid URL: </xsl:text>
-                <xsl:value-of select="mdxURL:whyInvalid(@ResponseLocation)"/>
-            </xsl:with-param>
-        </xsl:call-template>
-    </xsl:template>
-
-
-    <!--
-        Check for OrganizationURLs that aren't valid URLs.
-    -->
-    <xsl:template match="md:OrganizationURL[mdxURL:invalidURL(.)]">
-        <xsl:call-template name="error">
-            <xsl:with-param name="m">
-                <xsl:text>OrganizationURL '</xsl:text>
-                <xsl:value-of select="."/>
-                <xsl:text>' is not a valid URL: </xsl:text>
-                <xsl:value-of select="mdxURL:whyInvalid(.)"/>
-            </xsl:with-param>
-        </xsl:call-template>
-    </xsl:template>
-
-
 </xsl:stylesheet>
diff --git a/mdx/common-beans.xml b/mdx/common-beans.xml
index de41e26..12e52a6 100644
--- a/mdx/common-beans.xml
+++ b/mdx/common-beans.xml
@@ -714,16 +714,26 @@
         QNames for SAML metadata elements.
     -->
     <bean id="md-AdditionalMetadataLocation"  parent="QName" c:_0-ref="md_namespace" c:_1="AdditionalMetadataLocation"/>
+    <bean id="md-ArtifactResolutionService"   parent="QName" c:_0-ref="md_namespace" c:_1="ArtifactResolutionService"/>
+    <bean id="md-AssertionConsumerService"    parent="QName" c:_0-ref="md_namespace" c:_1="AssertionConsumerService"/>
+    <bean id="md-AssertionIDRequestService"   parent="QName" c:_0-ref="md_namespace" c:_1="AssertionIDRequestService"/>
     <bean id="md-AttributeProfile"            parent="QName" c:_0-ref="md_namespace" c:_1="AttributeProfile"/>
+    <bean id="md-AttributeService"            parent="QName" c:_0-ref="md_namespace" c:_1="AttributeService"/>
+    <bean id="md-AuthnQueryService"           parent="QName" c:_0-ref="md_namespace" c:_1="AuthnQueryService"/>
+    <bean id="md-AuthzService"                parent="QName" c:_0-ref="md_namespace" c:_1="AuthzService"/>
     <bean id="md-Company"                     parent="QName" c:_0-ref="md_namespace" c:_1="Company"/>
     <bean id="md-EmailAddress"                parent="QName" c:_0-ref="md_namespace" c:_1="EmailAddress"/>
     <bean id="md-GivenName"                   parent="QName" c:_0-ref="md_namespace" c:_1="GivenName"/>
+    <bean id="md-ManageNameIDService"         parent="QName" c:_0-ref="md_namespace" c:_1="ManageNameIDService"/>
     <bean id="md-NameIDFormat"                parent="QName" c:_0-ref="md_namespace" c:_1="NameIDFormat"/>
+    <bean id="md-NameIDMappingService"        parent="QName" c:_0-ref="md_namespace" c:_1="NameIDMappingService"/>
     <bean id="md-OrganizationDisplayName"     parent="QName" c:_0-ref="md_namespace" c:_1="OrganizationDisplayName"/>
     <bean id="md-OrganizationName"            parent="QName" c:_0-ref="md_namespace" c:_1="OrganizationName"/>
     <bean id="md-OrganizationURL"             parent="QName" c:_0-ref="md_namespace" c:_1="OrganizationURL"/>
     <bean id="md-ServiceDescription"          parent="QName" c:_0-ref="md_namespace" c:_1="ServiceDescription"/>
     <bean id="md-ServiceName"                 parent="QName" c:_0-ref="md_namespace" c:_1="ServiceName"/>
+    <bean id="md-SingleLogoutService"         parent="QName" c:_0-ref="md_namespace" c:_1="SingleLogoutService"/>
+    <bean id="md-SingleSignOnService"         parent="QName" c:_0-ref="md_namespace" c:_1="SingleSignOnService"/>
     <bean id="md-SurName"                     parent="QName" c:_0-ref="md_namespace" c:_1="SurName"/>
     <bean id="md-TelephoneNumber"             parent="QName" c:_0-ref="md_namespace" c:_1="TelephoneNumber"/>
 
diff --git a/mdx/validation-beans.xml b/mdx/validation-beans.xml
index 4e10120..248e0ff 100644
--- a/mdx/validation-beans.xml
+++ b/mdx/validation-beans.xml
@@ -12,6 +12,63 @@
         http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
         http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">
 
+    <!--
+        ***************************************
+        ***                                 ***
+        ***   U R L   V A L I D A T I O N   ***
+        ***                                 ***
+        ***************************************
+    -->
+
+    <!--
+        Shared validator beans.
+
+        The beans in this section have both "id" values by which they can
+        be referenced in Spring configuration, but also simpler "p:id"
+        values to simplify their contributions to error messages
+        composed from a series of component ID values.
+    -->
+
+    <!-- Reject "https://host:/xxx" because libxml2 has issues with that. -->
+    <bean id="validate_url_port" p:id="port" parent="mda.EmptyPortURLValidator"/>
+
+    <!-- Reject "https:///xxx" because it lacks an authority entirely. -->
+    <bean id="validate_url_host" p:id="host" parent="mda.MissingHostURLValidator"/>
+
+    <!-- Reject URLs which don't have an https:// protocol. -->
+    <bean id="validate_url_https" p:id="https" parent="mda.HTTPSProtocolURLValidator"/>
+
+    <!--
+        validate_url
+
+        Validate a string as a URL. Includes checking for port and host
+        issues.
+    -->
+    <bean id="validate_url" p:id="url" parent="mda.AsURLStringValidator">
+        <property name="validators">
+            <list>
+                <ref bean="validate_url_port"/>
+                <ref bean="validate_url_host"/>
+            </list>
+        </property>
+    </bean>
+
+    <!--
+        validate_https_url
+
+        Validate a string as a https:// URL. Includes checking for port and host
+        issues.
+    -->
+    <bean id="validate_https_url" p:id="url" parent="mda.AsURLStringValidator">
+        <property name="validators">
+            <list>
+                <ref bean="validate_url_https"/>
+                <ref bean="validate_url_port"/>
+                <ref bean="validate_url_host"/>
+            </list>
+        </property>
+    </bean>
+
     <!--
         ***********************************
         ***                             ***
@@ -220,6 +277,29 @@
     <bean id="check_mdui_xslt" parent="mda.XSLValidationStage"
         p:XSLResource="classpath:_rules/check_mdui.xsl"/>
 
+    <!--
+        check_mdui_logo_url
+
+        Section 2.1.5: Check the URL value of mdui:Logo elements.
+    -->
+    <bean id="check_mdui_logo_url" parent="mda.StringElementValidationStage">
+        <property name="elementName" ref="mdui-Logo"/>
+        <property name="validators">
+            <list>
+                <bean p:id="newline" parent="mda.RejectStringRegexValidator"
+                    p:regex=".*\n.*"
+                    p:message="mdui:Logo contains line break" />
+                <bean p:id="nbs" parent="mda.RejectStringRegexValidator"
+                    p:regex=".*\u00a0.*"
+                    p:message="mdui:Logo contains non-breaking space" />
+                <!-- Accept data: URLs with no further scrutiny. -->
+                <bean parent="mda.AcceptStringRegexValidator"
+                    p:regex="data:.*"/>
+                <ref bean="validate_https_url"/>
+            </list>
+        </property>
+    </bean>
+
     <!--
         check_mdui_logo_length
 
@@ -235,6 +315,21 @@
         </property>
     </bean>
 
+    <!--
+        check_mdui_urls
+
+        Check URL values of mdui:* elements other than mdui:Logo.
+    -->
+    <bean id="check_mdui_urls" parent="mda.StringElementValidationStage"
+        p:validators-ref="validate_url">
+        <property name="elementNames">
+            <set>
+                <ref bean="mdui-InformationURL"/>
+                <ref bean="mdui-PrivacyStatementURL"/>
+            </set>
+        </property>
+    </bean>
+
     <!--
         check_mdui
 
@@ -246,6 +341,8 @@
                 <ref bean="check_mdui_iphint"/>
                 <ref bean="check_mdui_xslt"/>
                 <ref bean="check_mdui_logo_length"/>
+                <ref bean="check_mdui_logo_url"/>
+                <ref bean="check_mdui_urls"/>
             </list>
         </property>
     </bean>
@@ -630,6 +727,45 @@
     <bean id="check_saml2meta" parent="mda.XSLValidationStage"
         p:XSLResource="classpath:_rules/check_saml2meta.xsl"/>
 
+    <!--
+        check_saml2meta_urlattrs
+
+        Check URL values of various attributes on md:* elements.
+    -->
+    <bean id="check_saml2meta_urlattrs" parent="mda.StringAttributeValidationStage"
+        p:id="saml2meta" p:validators-ref="validate_url">
+        <property name="elementNames">
+            <set>
+                <ref bean="md-AdditionalMetadataLocation"/>
+                <ref bean="md-AssertionConsumerService"/>
+                <ref bean="md-AssertionIDRequestService"/>
+                <ref bean="md-ArtifactResolutionService"/>
+                <ref bean="md-AttributeService"/>
+                <ref bean="md-AuthnQueryService"/>
+                <ref bean="md-AuthzService"/>
+                <ref bean="md-ManageNameIDService"/>
+                <ref bean="md-NameIDMappingService"/>
+                <ref bean="md-SingleLogoutService"/>
+                <ref bean="md-SingleSignOnService"/>
+            </set>
+        </property>
+        <property name="attributeNames">
+            <set>
+                <bean parent="QName" c:_0="Location"/>
+                <bean parent="QName" c:_0="ResponseLocation"/>
+            </set>
+        </property>
+    </bean>
+
+    <!--
+        check_saml2meta_urls
+
+        Check URL values of md:* elements.
+    -->
+    <bean id="check_saml2meta_urls" parent="mda.StringElementValidationStage"
+        p:id="saml2meta" p:validators-ref="validate_url"
+        p:elementName-ref="md-OrganizationURL"/>
+
     <!--
         check_saml_strings
     -->
@@ -719,6 +855,8 @@
                 <ref bean="check_saml2_lang"/>
                 <ref bean="check_saml2int"/>
                 <ref bean="check_saml2meta"/>
+                <ref bean="check_saml2meta_urlattrs"/>
+                <ref bean="check_saml2meta_urls"/>
                 <ref bean="check_saml_strings"/>
                 <ref bean="check_shib_noregscope"/>
                 <ref bean="check_shibboleth"/>