Hi ThereFirst the Environment: Server 2008, running Exchange 2010.Second, yesterday was the first time i touched Exchange 2010The issueIn the organization there are a number of people who's machines are not joined to the domain, for whatever reason, and they cannot be joined (XP Home, etc). Now we have setup their outlook to use the Exchange server as an SMTP and POP3 server. They are able to email anyone inside the domain without issue. They are however not able to email anyone outside the domain. They get a Relay Denied error. This happens over telnet as well.People who are part of the domain have no issue.Any ideas at all, please bare in mind that i havent got a clue of exchage 2010, so if at all possible please give me links to instructions. This appeared to be working. The server is brand new (less than two months old)

Hi Drazhar, You could set up Exchange account profile regardless if the client is joint domain. The user who is not authenticated can't relay email via Exchange server. Please check the following settings: Please go to Outlook | email account | more settings | Outgoing server, make sure "my outgoing server requires authentication " has been checked. Thanks, Elvis