This post will discuss the steps necessary to allow your SBS 2008 server to host POP3 and IMAP4 services for external clients. This process consists of four parts:
- Enabling the POP3/ IMAP4 services on the SBS 2008 server.
- Port forwarding POP3 /IMAP4 through the firewall to the SBS 2008 server.
- Configuring Exchange 2007 for authenticated client SMTP relay.
- Configuring POP3/IMAP4 and SMTP settings on the client.
Part 3 of this process has already been documented in the following blog post, which covers authenticated SMTP relay: How to Configure Trusted SMTP Relay in Exchange on SBS 2008.
Enabling POP3/IMAP4 on SBS 2008: After SBS 2008 setup completes, the POP3 and IMAP4 services are both stopped and set to manual for startup type. You can run the services.msc console to start them and change the startup type to automatic.
Launch the Exchange Management Console as administrator and expand Server Configuration > Client Access and click on the POP3 and IMAP4 tab. Here you can view the banner string, binding, authentication, connection, and retrieval settings for both services.