Assume the base URL of the page is:
http://mymachine.intranet.com/mypage.html
Page Content:
<a href="http://mymachine.intranet.com/mypage.html">
Rules
<Attribute name="href"/> or <Attribute name="href" tag="a"/>
Output
<a href=gateway-URL/http://mymachine.intranet.com/myhome.html>
Description
Because the URL to be rewritten is already an absolute URL, only the Gateway URL is prefixed to the URL.