If you use Small Business Server 2003 as your mail server and want to pick up email from a Gmail account via POP3 you may run into a little problem with the built-in POP3 Connector for Exchange 2003. Google requires SSL for POP3 access and the Exchange connector only supports basic POP3 connections.
After a little Googling I found some very handy instructions on how to get around this lack of functionality using a program called Stunnel.
Download the latest binary of Stunnel and install it. This program handles the SSL translation for you, and should include the required OpenSSL components.
Next you need to edit stunnel.conf in C:\Program Files\stunnel and in this file you need the following settings:
client=yes service=gmail [gmail] accept = 127.0.0.1:110 connect = pop.gmail.com:995
Save the config file and start Stunnel. You should see a little icon in your system tray.
Now configure the POP3 Connector to point to 127.0.0.1:110, and use your Gmail username and password, and hopefully it will now be able to download emails from your Gmail account.
My complete stunnel.conf:
; Sample stunnel configuration file by Michal Trojnara 2002-2006 ; Some options used here may not be adequate for your particular configuration ; Certificate/key is needed in server mode and optional in client mode ; The default certificate is provided only for testing and should not ; be used in a production environment cert = stunnel.pem ;key = stunnel.pem ; Some performance tunings socket = l:TCP_NODELAY=1 socket = r:TCP_NODELAY=1 ; Workaround for Eudora bug ;options = DONT_INSERT_EMPTY_FRAGMENTS ; Authentication stuff ;verify = 2 ; Don't forget to c_rehash CApath ;CApath = certs ; It's often easier to use CAfile ;CAfile = certs.pem ; Don't forget to c_rehash CRLpath ;CRLpath = crls ; Alternatively you can use CRLfile ;CRLfile = crls.pem ; Some debugging stuff useful for troubleshooting ;debug = 7 ;output = stunnel.log ; Use it for client mode client = yes service=gmail ; Service-level configuration ;[pop3s] ;accept = 995 ;connect = 110 ;[imaps] ;accept = 993 ;connect = 143 ;[ssmtp] ;accept = 465 ;connect = 25 ;[https] ;accept = 443 ;connect = 80 ;TIMEOUTclose = 0 ; vim:ft=dosini [gmail] accept = 127.0.0.1:110 connect = pop.gmail.com:995