There is an option under the SMTP virtual server advanced delivery properties just for this. HTH. Regards, Raj Periyasamy MCSE(Messaging), CCNA ________________________________ From: exchangelist-bounce@xxxxxxxxxxxxx [mailto:exchangelist-bounce@xxxxxxxxxxxxx] On Behalf Of Andrew English Sent: Thursday, June 01, 2006 7:05 AM To: exchangelist@xxxxxxxxxxxxx Subject: [ExchangeList] Re: IMF config Is there anyway to get IMF to drop emails that fail reverse lookup? Thanks Andrew