I setup mail using the guide here http://library.linode.com/email/postfix ... 0.04-lucid

I'm running Ubuntu 12 so I had to convert dovecot.conf format from old version 1 to 2.

All the shell tests and logs up to and including the mutt email client test indicate that email is working fine, but I can't connect to it via my desktop client, so I'm assuming I've messed up the MX records.

The above docs say about MX records "Please note that you'll need to modify the DNS records for any domains that you wish to handle email by adding an MX record that points to your mail server's fully qualified domain name."

For domain example.com, I have an A record (automatically generated) of:
Hostname: mail IP: 123.123.123.123 TTL: Default

And a single MX record of:
Mail server / FQDN: my.fqdn-example.com Preference: 10 Subdomain: mail TTL: Default

Domain name resolves correctly to website (so I know basic DNS is correct), but I can't connect to mail.example.com via my desktop email client, when using the correct username (full email address) and password.

And with ZERO real info we're supposed to what, guess?

Why would your email client care what your mx record points too?

MX records are ONLY used by the sending SMTP server.

_________________
Either provide enough details for people to help, or sit back and listen to the crickets chirp.
Security thru obscurity is a myth - and really really annoying.

Hey, I've never done this before. Thanks for your patience and understanding.

What "real" info would I need to post to solicit a well-considered, respectful response?

Things that come to mind: the address of your site, the email client you're using, and the error message that your client gives you.

The only domain I have setup on my Linode is bigpicturegames.com
I'm using Thunderbird 12.0.1 on Windows 7
When I try to create an account (either POP3 or IMAP) in Thunderbird I get "Checking password ..." then eventually receive the error "Configuration could not be verified - Is the username or password wrong?" (I've checked and they are correct)

When I test Dovecot (http://wiki2.dovecot.org/TestPop3Installation)
If I test Dovecot from my Linode shell I get "+OK Dovecot ready"
But if I test Dovecot from a remote shell I get "telnet: Unable to connect to remote host: Connection refused"

So, reading the advice on that Dovecot test page "If that didn't work, check all possible firewalls in between, and check that listen setting is * in dovecot.conf. "
I guess that's where I need to look next, unless someone has a better idea ...

EDIT: checked doveconf -a and "listen = *, ::" so that looks OK.

I can send email to info at bigpicturegames.com and read it fine using mutt in my Linode shell, but I can't connect via my desktop client.

"Connection refused" usually means that there is no daemon listening on the port in question. You can check using netstat -lvpnut - maybe you needed to restart Dovecot after changing the config?

With regards to MX records... you have no MX records currently...

http://www.intodns.com/bigpicturegames.com

_________________
Kevin a.k.a. Dweeber

I'd changed the MX record according to my interpretation of the Linode email guide. I've reverted back to the default MS record setup, but still can't access email from desktop client.

I checked the logs and it looks like dovecot can't connect to the mail user authorisation database. I checked my dovecot-sql.conf and that seems to be OK.

Error in mail.err log:

Jun 21 22:42:07 localhost dovecot: auth-worker: Error: mysql(127.0.0.1): Connect failed to database (mail): Access denied for user 'mail_admin'@'localhost' (using password: YES) - waiting for 25 seconds before retry

Have double and triple checked the password, so not quite sure what's going on.

Thanks to everyone who helped me.

I finally got the mail server working on Ubuntu 12.04 and have documented the changes I had to make to the most recent published guide (Ubuntu 10.04) here: viewtopic.php?f=11&t=9047