mail from "nobody"

[Bob Reven]

i am using IMP 2.2.4 on an intel redhat linux 6.2 system with exim 3.22

all emails sent by IMP have a return-path of nobody@unix1 eg,

Return-path: <nobody@unix1.trinity.ox.ac.uk>

and a 'sender' field of nobody also:

Sender: Nobody <nobody@unix1.trinity.ox.ac.uk>

is this how its supposed to be? is this how you have it setup. i occassionally
get replies addressed to nobody@unix1.trinity (do these people have broken
mail clients?) which does come to me but still hardly very satisfactory!

i would quite like the Return-Path: and Sender: to be the same as the "From:"
that is defined in the compose webpage. i realise this is probably because 
apache runns as user nobody but is there any way round this. have i setup badly?

any thoughts on how you do it would be most appreciated

many thanks

Bob Reven