diff --git a/en_US.ISO8859-1/books/handbook/security/chapter.xml b/en_US.ISO8859-1/books/handbook/security/chapter.xml
index 33365fdcff..c177a495a3 100644
--- a/en_US.ISO8859-1/books/handbook/security/chapter.xml
+++ b/en_US.ISO8859-1/books/handbook/security/chapter.xml
@@ -1742,7 +1742,7 @@ kadmind5_server_enable="YES"</programlisting>
 
 	<listitem>
 	  <para><link
-	      xlink:href="http://www.ietf.org/rfc/rfc4120.txt?number=4120">RFC
+	      xlink:href="https://www.ietf.org/rfc/rfc4120.txt">RFC
 	      4120, The <application>Kerberos</application> Network
 	      Authentication Service (V5)</link></para>
 	</listitem>
@@ -1756,7 +1756,7 @@ kadmind5_server_enable="YES"</programlisting>
 
 	<listitem>
 	  <para><link
-	      xlink:href="http://www.pdc.kth.se/heimdal/">Heimdal
+	      xlink:href="https://www.h5l.org/">Heimdal
 	      <application>Kerberos</application> home
 	      page</link></para>
 	</listitem>