How to Set Up Windows Server as a SMTP Relay Server

This article descript how to configure your internal Windows servers that would need to send emails to all domains on the Internet. It is recommended to only allow the minimum, necessary hosts to openly relay to all domains.

1. Run IIS.
1. Right click on the Default SMTP Virtual Server and select Properties.
2. On the Access tab, click Relay.
3. Click Only the list below, click Add, and then add the hosts that need to use this SMTP host to send email. On the dialog box that appears, you have the following options:
o Single computer: Specify one particular host that you want to relay off of this server. If you click the DNS Lookup button, you can lookup an IP address of a specific host.
o Group of computers: Specify a base IP address for the computers that you want to relay. You have to specify the octets in the IP address for hosts that you will allow to relay. For example: If the IP address is 192.68.7.21, and you want any hosts with the first two octets 192.68 to relay, specify 255.255.0.0 for the subnet mask.
o Domain: Select all of the computers in a domain by domain name that will openly relay. This option adds processing overhead, and might reduce the SMTP service performance because it includes reverse DNS lookups on all IP addresses that try to relay to verify their domain name.

Post your questions, comments, feedbacks and suggestions

Contact a consultant