and i have given in acs-mail-lite parameters:
BounceDomain: smtp.gmail.com SendmailBin SMTP
what else to be configured.
so what else to be done?
What version of OpenACS are you using?
Also you may want to check on the configuration of your local mail server. OpenACS will use your mail server to send emails out so if you can't reach any domain but yours, it's probably related to the configuration of your local mail server.