question about the client ip sent to back-end server

[Sharl.Jimh.Tsin]

hi,everyone
  now i have a problem about the IPs from cache server to web
server.that is,my varnish runs on port 80 in the front,and there is a
hiawatha server running on port 81.for cache,I deny all requests from
81 port for someone access the back-end server directly,configuration
in the hiawatha is:
_______
allow 127.0.0.1,localhost etc.
deny all.
_______
it seems that it is OK now.BUT the poll plugin on my website breaken
now :( Once one person polled,then other visitors can not poll again
due to the poll plugin's keep-state.
the poll plugin distinguish the visitor has polled or not by its
IP,and in fact all visitors request the hiawatha via varnish on the
same ip,it is 127.0.0.1.
it is really a conflict!!

is there any solution? my friends? thanks!

Best regards,
Sharl.Jimh.Tsin (From China **Obviously Taiwan INCLUDED**)