Hello, I use Exchange 2007 and I've got an accepted domain that is used internaly for sending communication. The accpeted domain is called Compa.inter: DomainName : Compa.inter DomainType : Authoritative AddressBookEnabled : True Default : False AdminDisplayName : ExchangeVersion : 0.1 (8.0.535.0) Name : Compa.inter DistinguishedName : CN=Compa.inter,CN=Accepted Domains,CN=Transport Identity : Compa.inter Guid : 92340a72-72312347cd-b974-f674523 ObjectCategory : Compa.inter/Configuration/Schema/ms-Exch-Accepted-Domain ObjectClass : {top, msExchAcceptedDomain} WhenChanged : 15/05/2008 18:16:05 WhenCreated : 13/05/2008 11:18:05 OriginatingServer : DOMCONT.Compa.inter IsValid : True I found out that I do receive emails from outside and I would like to prevent that! How may I only use that accepted domain ONLY internaly? Any ideas?? Graig

What defines "outside" vs "inside"? When sending from an internal exchange mailbox to another internal exchange mailbox, the smtp address of the user isn't shown anyway. Do you mean from other internal mail systems that are external to exchange? I’m not sure I understand the scenario here, but you could mark the “internal” users with the “require authentication”. This would, in effect block external submissions to these users. (Set-Mailbox -RequireSenderAuthenticationEnabled $true ) Mike Crowley Check out My Blog!

What defines "outside" vs "inside" When sending from an internal exchange mailbox to another internal exchange mailbox, the smtp address of the user isn't shown anyway. do you mean from other internal mail systems that are external to exchange? I’m not sure I understand the scenario here, but you could mark the “internal” users with the “require authentication”. This would, in effect block external submissions to these users. (Set-Mailbox -RequireSenderAuthenticationEnabled $true ) Mike Crowley Check out My Blog!

Another idea, add the domain to your email address policy but don't add it to your accepted domain.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

I like James' idea better, however I still don't understand why you would need a private SMTP namespace for a single Exchange org. Can you elaborate on this so that we can be sure to reply with sound advice? Mike Crowley Check out My Blog!

Hello Mike, Some application sends alerts to users inner our organization (Compa.inter) nobody from outside the oragnization should contact them using that email address. Thanks for your help. Graig