How it's possible to configure?
Virtual hosts in Apache?

Cookies are stored per domain with no port included. There is nothing we can do about it.

it can be configured with virtual hosts, multiple http daemons, port forwarding and probably a hundred other methods

apparently, there might be some way to manipulate Set-Cookie header[1], although google handbook[2] description made it all sound quite non-specified, and it is likely that it wouldn't work in msie anyway.

as such i believe we won't be trying to fix this by that header manipulation - but this should be documented somewhere (it's ok to document for 2.0 only)

maartinjsh, i'll assign this one to you
if anything is unclear, please, ask.

[1] http://stackoverflow.com/questions/1612177/are-http-cookies-port-specific
[2] http://code.google.com/p/browsersec/wiki/Part2#Same-origin_policy_for_cookies

A note on this behavior added at:

http://www.zabbix.com/documentation/2.0/manual/web_interface

thanks, closing