redirecting webpage (finding out the name of the server)

[stig]

hi

in a web-application we use a form where people enter some information.
when they save the information the page should save and then redirect to
another page. as far as i know to redirect the has to use non-relative
path to redirect to.
and here comes the problem, we use two servers and round robin, so i
would like the script to redirect to the currently used server.

is it at all possible to make relative redirections (not giving entire
server path ie: http://www1.some.com/cgi-bin/next_page.cgi)?

or, how do i find out the name or IP of the server that is used
currently (www1.some.com or www2.some.com) so that i can build a
non-relative path myself?

thanks in advance
stig