[Zope] Tag BASE without port number

Hi all, is it possible to hide port bumber in case of reverse proxy redirecting? I have POUND as reverse proxy and Zope 2.10.13 on port 930, but html BASE tag contain this port number, which I does not want to have there. I do not want to explicit specify base tag at all pages. I prepare new installation, but I cannot remember nor find what I was make before at my old installation, it is 5 years ago. Google does not help me. Many thanks, J. Lukesh