I need to prevent a specific group of users to send and receive externalmail(outside ofour domain). Does anybody know a solution?? w.k.r. Eric

Hi Eric, Is it Exchange 2007? if yes then follow this procedure. Create a Distribution Group "NoInternetMail" & add all recipients who doesnt required to send & receive internet email. Prevent form Sending Mails: Create a transport rule on Hub Transport Server: Organization Configuration -> Hub Transport -> Transport Rules -> New Transport Rule -> Give Name TR No Internet MailConditions: select "From a member of a distribution list" & select created group "NoInternetMail" Select another condition "Sent to users inside or outside the organization" & Select Outside. Actions: select "send bounce message to sender with enhanced status code" & write your custom message like You are not authorized to send mails to internet Prevent from Receiving Mails: New User: You can select require that senders are authenticated while creating new users which will stop receiving mails from internet. User -> properties -> Mail Flow Settings -> Message Delivery Restrictions -> Properties -> set Sender Authentication. For Existing Users: You have already crated a group "NoInternetMail" & added users so set sender authentication for all members with this single command. Get-DistributionGroup "NoInternetMail" | Set-Mailbox -RequireSenderAuthenticationEnabled $true

Hi Amit,I'm sorry but its exchange 2003.

Hello Eric, In Exchange 2003, this would explain you... Restricting users from Sending and Receiving Internet Mail in Exchange 2003