Applies to all versions of SmarterMail
NOTE: This KB article provides guidelines for most installations regarding the items that need configured on your DNS server. It does not explain how to configure your DNS server.
There are three major items to set up on the DNS server for each domain added to SmarterMail: An A or CNAME record, MX record, and PTR or reverse DNS record. In addition, you should set up DNS authentication records such as SPF (Sender Policy Framework), DKIM, and DMARC records. Helpful, though not mandatory, records can also be created for Autodiscover, which helps when connecting clients to your SmarterMail account.
How you set up these records is dependent on who hosts your DNS server and the DNS software used. Check your DNS server documentation for instructions on how to set up the following records.
WebMail URL (A Record)
Add an A or CNAME record for mail.example.com (or whatever domain you want to use) that points to the IP address of your webmail interface. This will allow users of that domain to access webmail by typing http://mail.example.com or http://mail.example.com:9998 in their Web browser (depending on whether you use IIS or the included Web server).
Mail Pointer (MX Record)
Add an MX record for the domain that points to mail.example.com. This will allow other email servers to locate your mail server.
PTR (Reverse DNS Record)
PTR records resolve IP addresses into hostnames. By setting up a PTR record, the receiving server can do a reverse DNS lookup to verify the sender.
SPF (TXT Record)
Some large email providers like Gmail, Microsoft 365, Hotmail, and others are now requiring specially formatted TXT records to be added to your DNS server. One of these is an SPF (Sender Policy Framework) record. Information about how these records should be formatted can be found at Dmarcian. Please keep in mind that the owners of the domains may have significant input on what goes into these records.
DKIM (TXT Record)
Another special DNS record is DKIM (DomainKeys Identified Mail). This record can be created from within SmarterMail for specific domains by a system administrator, or domain administrators can create them on their own. Regardless, the information contained within the domainKey created by SmarterMail should be added to the domain's DNS entry.
DMARC (TXT Record)
DMARC is the final special record that needs to be created. DMARC is essentially a confirmation of the SPF and DKIM records that were created. Again, information about how these records should be formatted, as well as a wizard to walk through for creating a DMARC record, can be found at Dmarcian.
Helpful Record Types
Setting up the below record types will make it easier for users when setting up their email accounts in clients, or using third-party apps.
Autodiscover (SRV and A or CNAME Records)
There are 2 types of Autodiscover records you can create. The SRV record is used to locate the Autodiscover service for a particular domain. The A or CNAME record maps a domain to the IP address of the server that hosts the autodiscover service. It's not necessary to add both records, but the SRV record is strongly suggested.
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