Comodo Firewall 3 is great - but intimidating to a newcomer due to advanced design (which is really great). Not to worry!!! What Comodo must have is a NEW USER button stating:
Email Access: To access email open Comodo 3, go to Firewall Tab (on top) / Choose: “Define a New Trusted Application.” When “Define a New Trusted Application” popup appears, select running processes. Now search for your email client, highlight it, then press “Select.” Now you will be able to SEND and RECEIVE email.