If your .forward file starts with "# Exim filter", then the Exim mail program can do some processing of your incoming email.
If you have exim installed, you can probably find comprehensive documentation on this in
/usr/share/doc/exim/filter.txt{,.gz}
otherwise have a look online at www.exim.org/exim-html-3.30/doc/html/filter.html or www.exim.org/exim-html-4.00/doc/html/filter.html depending on which version of exim you have installed.
if error_message then finish endif
if $header_received: contains remotehost\\.co\\.nz
and $header_from: does not contain remotehost\\.co\\.nz
then
save $home/Mail/remotehostspam 0600 seen finish
endif
deliver thisemailaddress@verisign.com finish
2 pages link to EximFilter:
lib/main.php:944: Notice: PageInfo: Cannot find action page