issue in mail command

I have used the mail command from the command line for sending mail from one machine to anther machine.

Example:

mail -s "Test" thillaselvan@xxx.co.in
Testing

But the mail is not getting received.
I have checked the logs in the following file.

tail -f /var/log/exim4/mainlog

It is logging the following message.

2011-07-21 18:07:37 1QjsVV-0001Q9-BS ** thillaiselvan@bksys.co.in R=nonlocal: Mailing to remote domains not supported

Why it is not sending the mails in this machine to other machines?.

What needs to be done?

If I checked the mail from my local machine means it is working.

Kindly guide me.
Thanks in advance!

---------- Post updated 07-22-11 at 08:36 AM ---------- Previous update was 07-21-11 at 06:56 PM ----------

Dear All,
Any solution please...
Thanks in Advance!