Occasionally as you browse through clicking on links in an Ultranet site, authenticated (signed in) users may find that instead of being taken to that linked page, they get returned to the home page and appear to have been signed out. This article explains the behaviour and how to get around it.
For example, let's say Tauira School has their own web address (www.tauira.school.nz) and they use Ultranet as their school website. The school can map this personal web address, so that it connects to the Ultranet application (tauira.ultranet.school.nz). Once mapped, both addresses will resolve to the same Ultranet site—but they are still technically two separate domains.
Pre-Ultranet 2.6 user authentication paths.
This last bit is important, because this relates to how authentication is handled. Since Ultranet 2.6, when users sign in to Ultranet they will be redirected to use the secure Ultranet domain (*.ultranet.school.nz) for authentication, even if they may have browsed to the site using their custom school domain.
Redirection behaviour post-Ultranet 2.6.
However, if the authenticated user then clicks on a link that refers to the non-Ultranet domain, this would result in the user being kicked back to the Home page and appearing to be signed out. Because the two domains are separate (even though they both point to the same location), authentication only binds to one or the other. So as far as the security protocol is concerned, going from "tauira.ultranet.school.nz" to "www.tauira.school.nz" is like jumping between two unrelated websites.
Absolute vs Relative links
To avoid this inconvenient behaviour from arising, use a relative link rather than an absolute link. Here's an example:
Absolute link: http://www.tauira.school.nz/WebSpace/16/
Relative link: /WebSpace/16
As you will see in the example above, the relative link just requires the bit after the domain, rather than the whole URL path. This means it will ignore if the user is on the school or Ultranet domain, leaving the security mechanism to connect the user using whatever domain they are currently viewing on.