Hi;

I am using Exchange 2013 standard, I want to find a solution of writing a script to integrate with my Exchange 2013 which allow to detect the email domain of recipients, if the email domain is any company instead of internal company, a warning message should send back to email sender.

Is it able to

Not with a script but you should just be able to use Transport Rules to do that https://technet.microsoft.com/en-us/library/dd351127(v=exchg.150).aspx eg http://exchangeserverpro.com/restrict-outbound-email-transport-rule/ or look at writing a Transport Agent http://blogs.msdn.com/b/mstehle/archive/2010/03/10/howto-return-to-sender-transport-agent-sample.aspx

Cheers
Glen

Hi Kane,

You might consider using Mail Tips, which would generate warning even before emails are sent to external user. It warns right on filling the TO: CC: BCC: fields.

MailTips:

https://technet.microsoft.com/en-us/library/jj649091(v=exchg.150).aspx

The External Recipients MailTip is displayed if the sender adds a recipient that's external, or adds a distribution group that contains external recipients.

This MailTip informs senders if a message they're composing will leave the organization, helping them make the correct decisions about wording, tone, and content.

Set-OrganizationConfig -MailTipsExternalRecipientsTipsEnabled $true

Set-OrganizationConfig:

https://technet.microsoft.com/en-us/library/aa997443(v=exchg.150).aspx