we are getting lot of spam mails , when i check the options was able to see ip address from where the email was sent.94.79.49.117 how to block any emails from those provider's who has this ip, not just one block all originating from this ip area group. is it possible? Thank you very much for the info.

You could create a firewall rule to disallow SMTP traffic from these source IPs. What version of Exchange? If 2007/2010, you can either install an Edge server or install the anti-spam agents on the HUB server and configure block list.Tim Harrington - Catapult Systems - http://HowDoUC.blogspot.com

How to Add IP Addresses to the IP Allow List and IP Block List http://technet.microsoft.com/en-us/library/bb123801(EXCHG.80).aspx