I currently download from a postfix/dovecot arrangement to ms outlook on a windows pc

I want instead to download to a linux local host, that has a static external IP, but no FQDN on the localhost itself, and in which roundcube and postfix are installed.

I am somewhat confused about the imap and smtp settings required of roundcube

Anyone has any ideas here pls?
Thanks

You can use fetchmail to grab the mail from the external pop server.
You will need to install an IMAP server (dovecot is easy & good) for roundcube to talk to.
For smtp from roundcube, presumably your local postfix is configured to route outbound mail?

thanks...there are two things I'm not sure of
1. Mail is to reside permanently on that linux computer...it is not planned to download it subsequently from the local server. So do I still need dovecot?
2. In terms of adding users....does this need to be done on the local server, to correspond to the mail account names?

Compused

Yes.
Presumably your intention is to use Roundcube webmail on the new linux box rather than a mail client on whayever client pc's.
Roundcube requires an IMAP server, it cannot read mail directly from the filesystem.Yes. The MTA (postfix) needs a list of valid users to deliver mail to, and dovecot needs to authenticate users and be able to find their mail to supply via the roundcube web interface.
You can use LDAP or *SQL etc. but the simplest is just creating system users.
The dovecot documentation and wiki is very good and should give you all the info required.

Ok, thanks again