[imp] version of kernel, Redhat for imp running

[Imp User]

Dear all,

Would you mind sharing your experience on choosing which version of 

i.  kernel (2.2.x / 2.4.x) 
ii. distribution (Redhat,Mandrake,...)
iii.php version
iv. hardware config

when I want to setup Imp 3.1 to serve over 1000 users, each assume having 
mailbox of maximum 100MB. 

Many thanks.


Thanks and regards,
Boris