How to setup mozilla mail client to connect to IMAP server


Introduction

IMAP mail servers have the advantage that mail can stay on the server so you can see the same mail from any number of client computers that you might use. This means several people could share a mail account. This is in contrast to the usual account offered by ISPs which is a POP mail server and the mail will then usually disappear from the server after it is collected by any one client.

Security

It is possible that your connection to the ISP is available to be snooped by malicious persons who might see your login and password and later pretend to be you or just read your mail themselves. It is always wise to insist that your ISP always allows a secure connection encrypted using SSL or TLS. The secure protocols are usually given different port numbers. So always select "SSL" or "TLS" which will use port 993.

Setup

The administrator will have given you a login name and password and the name of the mail server machine. This may or may not match the email address. Don't confuse login name with email address. E.g the email address may be "ceramics@terrarusticat.co.uk" but the login name may be "pilar" and the server name may be "ns2.cyterm.com"

You must create a new mail account using your mail client (e.g. mozilla mail or microsoft outlook) Ensure that you select IMAP as the type of account (not POP).

The account server settings will be as shown in the screen below:-
IMAP mail client configuration


You may not need any special configuration for the outgoing mail connection (SMTP) since your ISP should already have SMTP configuration details. However if you need to use a different mail server for outgoing calls, then something similar to the screenshot below may be suitable. Good clients will allow STARTTLS negotiation on ports 25 or 587 but Outlook clients may have to use forced TLS on port 465. (note newer mozilla browsers allow a choice of SSL or TLS. Choose TLS always) :-
Secure TLS SMTP outgoing mail

Caveat

When using secure connections (SSL or TLS) a server digital certificate is used to verify the authenticity of the mail server to the client. If the certificate is self-signed (as it is for "ns2.cyterm.com") then it is likely that the mail client will pop-up a warning dialog about the certificate.  Accept the certificate as valid for this session only (not for all time). You will then be able to make one mail read session or one mail write session. A second session is likely to fail due to certificate problems and the solution is to close the mail client and all browser windows and then restart the mail client. You will see the certificate warning at every session and again should only accept for the current session. The fix for this annoyance would be for the server owner to buy a certificate from a known certificate authority but this does cost much money.