We have Exchange 5.5 on Windows NT 4.0 behind the Raptor Eagle 6.0 Firewall. The user wants to get their mails from outside using different programms. They can get their mails very well, but if they want to send mails to an outside adress, they get an error message like this: 550 invalid domain.
what can we do to allow them sending mails?
what can we do to allow them sending mails?