Set the Plesk server hostname and secure the panel with SSL

A fresh Plesk server often uses a temporary hostname and a self-signed certificate, so browsers show a warning on https://server:8443 and email clients complain about the mail certificate. Setting a real hostname and a Let's Encrypt certificate fixes both in a few minutes.

Before you start

• Plesk administrator access.
• A hostname you control, for example server1.example.com, with an A record pointing to the server's IP. It must not be a domain hosted as a website on the server.
• Reverse DNS for the IP set to the same name helps email delivery; on a VPS see set rDNS in Virtualizor.

Change the hostname

1. Go to Tools & Settings → Server Settings (under General Settings).
2. Enter the Full hostname, for example server1.example.com.
3. Click OK.

From the command line, the same can be done with plesk bin server_pref --update -hostname server1.example.com.

Secure Plesk with Let's Encrypt

1. Go to Tools & Settings → SSL/TLS Certificates (under Security).
2. In the Certificate for securing Plesk section, click + Let's Encrypt.
3. Confirm the hostname and enter an email for renewal notices.
4. Click Get It Free.

Plesk now uses the certificate for the panel on port 8443 and renews it automatically. The Security Advisor extension offers the same with one click; see Security Advisor.

Secure the mail server

On the same page, choose the certificate for Mail server (and Webmail, if offered) and select the Let's Encrypt certificate you just issued. Mail clients connecting to server1.example.com for IMAP and SMTP then see a valid certificate. Customers can also secure their own mail domain in SSL It!; see SSL It!.

Panel access URL

• Plesk listens on https://server1.example.com:8443 (and 8880 for HTTP).
• Under Tools & Settings → Customize Plesk URL, you can let customers reach Plesk at https://example.com/plesk or a dedicated subdomain on port 443 – handy when offices block port 8443.
• Restrict panel access to known IPs under Tools & Settings → Restrict Administrative Access for extra security.

Troubleshooting

• Let's Encrypt fails for the hostname: the A record does not point to the server, or port 80 is blocked.
• Browser still warns: you are opening Plesk via IP address. Use the hostname.
• Mail clients warn: they connect to mail.customerdomain.com, not the hostname. Use the hostname as server, or secure the customer's mail domain.
• Hostname resets after reboot: cloud-init may override it on some VPS images; set preserve_hostname: true.

Next steps

• Manage IP addresses.
• Keep Plesk updated.
• Install Plesk on a VPS.