[sf-lug] Sendmail configuration

[Deepan]

Hi All,
I am using sendmail via php mail function to send
emails. However few servers reject my mails with
the error 'Sender address rejected: Domain not
found', since mails from my server are sent as
email at localhost.localdomain. How do I change this
to a valid domain name ? We only own a public IP.
we dont really have a domain name, is it possible
to use IP ? 
Regards
Deepan
Facebook Sudoku Solver:
http://apps.facebook.com/sudokusolver/ 
Sudoku Solver: http://www.sudoku-solver.net/ 
Home Page: http://www.codeshepherd/