abhishek singh wrote: > i have solved one problem that was 1st example in my previous mail. > means now no unknow user from my domain can send mail to my real users > of mydomain but still there is 2nd problem means anyone can telnet to my > server and can forge real domain address to sendmail to my domain users > like Tell you what. Just ditch the whole sendmail thing and use postfix. If you are not using virtuser table, there should be very little, if not zero, changes. http://www.postfix.org/ADDRESS_VERIFICATION_README.html Postfix can do both with a few config lines natively. Just take note that some people do not appreciate callback verification.