[exim] Incoming SMTP Problems (Revised)

Hello,

I'm trying to send mail to my exim4 mail host via a mail client SMTP
connection and it's not working.

My machine is configured as a smarthost, meaning it relays all incoming
SMTP traffic to my ISP's SMTP server. Otherwise, all incoming mail is
stored in the user's mail directory for them to retrieve.

When I send mail from my client, this line is added to my mainlog file:
2005-01-18 15:13:13 no host name found for IP address xxx.xxx.xxx.xxx
2005-01-18 15:13:13 H=([xxx.xxx.xxx.xxx]) [xxx.xxx.xxx.xxx]
F=<miked@???> rejected RCPT <miked@???>: relay
not permitted
2005-01-18 15:13:17 unexpected disconnection while reading SMTP command
from ([xxx.xxx.xxx.xxx]) [xxx.xxx.xxx.xxx]

...and this line is added to my rejectlog file:
2005-01-18 15:13:13 H=([xxx.xxx.xxx.xxx]) [xxx.xxx.xxx.xxx]
F=<miked@???> rejected RCPT <miked@???>: relay
not permitted

What I am ultimately trying to achieve here is to be able to send mail
from my client to my SMTP server, which is forwarded to my ISP's SMTP
server. I'd really prefer to have the connection encrypted (either TLS
or SSL) and not open.

Something I forgot to mention... If the user's mail client can be
authenticated with a valid username/password, I'm fine with them making
a connection to my SMTP server.

Thanks for your help,
-MikeD