OpenSRS delivers hosted email through two server clusters, Cluster A and Cluster B. Your cluster is assigned automatically when your account is set up, and every email account you create as a reseller lives on that same cluster. This article shows you how to find your cluster and lists the DNS records and port settings you need to configure hosted email.
About email clusters
A cluster is the group of OpenSRS mail servers that hosts your email accounts. Cluster A and Cluster B offer identical features and functionality. The cluster you are on differs only in the server hostnames you use in DNS records and mail client settings.
Cluster assignment is random and cannot be changed. Because all of your email accounts share one cluster, you only need to identify it once before configuring DNS or mail clients.
Note: The server hostname is spelled hostedemail. Keep the "e" in "email" or the records will not resolve correctly.
Step 1: Find your email cluster
You identify your cluster in the Reseller Control Panel.
- Sign in to the Reseller Control Panel.
- Click the Email tab and select Settings.
- Find your cluster under Cluster Name.
DNS records required to set up hosted email
For hosted email to work, your domain needs two core DNS records: an MX record and a CNAME record.
The MX (Mail Exchange) record identifies the mail servers that receive email on behalf of your domain and tells the rest of the internet where to route messages.
The CNAME (Canonical Name) record maps one hostname to another. Point a subdomain such as mail.example.com to the OpenSRS server with a CNAME so your clients can use it as their incoming and outgoing server and as a custom webmail sign-in URL.
The exact values depend on your cluster. Cluster B records include an extra .b. When you apply these settings, replace yourdomain.com with the domain you are configuring.
DNS records for Cluster A
Setting | Value |
|---|---|
MX record | mx.yourdomain.com.cust.hostedemail.com |
CNAME | mail.yourdomain.com.cust.hostedemail.com |
IMAP / POP / SMTP hostname | mail.hostedemail.com or mail.emailhome.com |
Webmail sign-in | https://mail.hostedemail.com or https://mail.emailhome.com |
DNS records for Cluster B
Setting | Value |
|---|---|
MX record | mx.yourdomain.com.cust.b.hostedemail.com |
CNAME | mail.yourdomain.com.cust.b.hostedemail.com |
IMAP / POP / SMTP hostname | mail.b.hostedemail.com or mail.mailconfig.net |
Webmail sign-in | https://mail.b.hostedemail.com or https://mail.mailconfig.net |
Port numbers for Cluster A and Cluster B
Both clusters use the same ports for mail client connections.
Protocol | SSL enabled | SSL disabled | TLS |
|---|---|---|---|
IMAP | 993 | 143 | n/a |
POP3 | 995 | 110 | n/a |
SMTP | 465 | n/a | 25, 587 |
Next steps
- Configure your DNS records. Once you know your cluster, apply the MX and CNAME records to your domain. See Configuring DNS for OpenSRS Hosted Email.
- Set up the email service. Create your domain and mailboxes in the Reseller Control Panel.
- Add a custom webmail URL. Use a CNAME to give your clients a branded sign-in address. See the custom webmail login guide.
Questions? Contact OpenSRS Support.
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