OK, I have read the K9 doc, the avast help and posts related to proxy.
The K9 email filtering program uses a POP3 proxy server to analyse the incoming mail from the 110 port and uses the 9999 port to make the mail available to the email application (Outlook Express here).
The K9 settings for Outlook Express are:
POP3 server: 127.0.0.1
user name: pop3.tiscali.com/110/robin
I will make the following settings to allow Avast! 4.1 to sits between K9 and Outlook Express
C:\Program Files\Alwil Software\Avast4\DATA\avast4.ini
[MailScanner]
DefaultSmtpServer=smtp.tiscali.com
DefaultPopServer=127.0.0.1:9999 -- Avast! sees the incoming mail on 9999 port
UserDefaultSmtp=0
PopListen=127.0.0:111 -- Outlook Express sees the incoming mail on 111 port
Outlook Express
POP3 server: 127.0.0.1:111 -- changed from 127.0.0.1
user name: pop3.tiscali.com/110/robin -- unchanged!
SMTP server: 127.0.0.1 -- changed from smtp.tiscali.com
enable SMTP authentification
user name for SMTP server: robin#smtp.tiscali.com
comments welcome! seems that some gurus are looking these posts
cymago