Quoting Matt Goodall firstname.lastname@example.org:
This is a common problem with proxied applications. It affects anything that generates URLs.
You need to add a nevow.vhost.VHostMonsterResource to your site. See the docstring for details, including how to configure the Apache proxy.
Well in fact I use a resource wrapped in a guard.SessionWrapper to get the authentication functionnality, and the only solution I've seen for using vhosts is the small hack found here : http://twistedmatrix.com/pipermail/twisted-web/2004-October/000801.html. There's not seem to have a clean solution for this problem, and I'm not (yet :)) able to judge if I should use this.