Transferring users( shadow and passwd ) files

[Nathan Ridge <ridgey@mackay.matilda.net.au>]

I have recently had a system crash on one of our main servers, what we
decided to do after the crash is have several machines doing a certain task
each e.g one for mail one for webserver one for radius so on and so forth.
The problem is, i have copied the shadow and passwd files onto the mail
server but when a user tries to pop retrieve is says -ERR passwd incorrect
even when the passwd is correct.  The only way is to do a userdel and then
adduser again and this seems to fix the problem.

1. Is there other files or something else i need to do to make it work
properly?

2. Im running CUCIPOP, is there a way to make it authenticate to  another
machine then retrieve mail?

any help much appreciated