MAIL
Mail servers also use other DNS records. For example, servers that receive Internet mail perform a reverse lookup to a DNS PTR record to determine the host name for a given IP address. Reverse lookups are useful in verifying the source of a message, an important tool for restricting relay access through your server or preventing unsolicited commercial e-mail (UCE).
You must correctly configure DNS to support your use of SMTP. To determine the IP address of the mail server for the destination domain, IBM® Lotus® Domino® does the following:
1. The server looks up the domain part of each recipient's address in DNS.
2. If DNS finds an MX record, the server tries to connect to the server listed in that MX record. If there is more than one MX record, the server tries to connect to the record that has the lowest cost. If more than one MX record has the lowest cost, the server randomly selects one and tries to connect to the server listed in that MX record.
4. If DNS does not find a record, Domino cannot deliver the message and sends a nondelivery message to the sender.
An MX record maps a domain name to one or more host names. An A record maps a host name to the IP address of a server. You may want to use a host name in the MX record instead of just an A record for the following reasons:
For example, the acme.com domain has four MX records:
Related topics