This page explains how to set up SquirrelMail on Linux to access a remote IMAP sever. Web.de is used as an example
cd squirrelmail; chown -R root:rootsquirrelmail/data/ and squirrelmail/attach/ folders in /var/local/ and make them writeable for to the webserver (chown to user and group of apache process) Protect web access to subfolders
 Protect web access to subfolders
Run config/conf.pl:
web.deimap.web.de, Port 143smtp.web.de, Port 25
All settings are stored in config/config.php. This is an excerpt with the important settings:
$squirrelmail_default_language = 'en_US'; $default_charset = 'utf-8'; $domain = 'web.de'; $imapServerAddress = 'imap.web.de'; $imapPort = 143; $useSendmail = false; $smtpServerAddress = 'smtp.web.de'; $smtpPort = 25; $pop_before_smtp = false; $imap_server_type = 'other'; $invert_time = false; $trash_folder = 'Papierkorb'; $sent_folder = 'Gesendet'; $draft_folder = 'Entwurf'; $data_dir = '/var/local/squirrelmail/data/'; $attachment_dir = '/var/local/squirrelmail/attach/'; $smtp_auth_mech = 'login'; $imap_auth_mech = 'login'; $use_imap_tls = false; $use_smtp_tls = false;
More Info here
Everything done in Options
sans-10 looks good Optionally set Folder Preferences → Auto Refresh Folder List:
 Optionally set Folder Preferences → Auto Refresh Folder List: never if you want to avoid page reloads