How to Identify and Resolve Expired Self-Signed or CA-Signed SSL Certificate Issues in Postfix on Red Hat Enterprise Linux?

Issue

• A self-signed SSL certificate used by the Postfix mail server has expired. This was reported by a security scanner or monitoring solution.

• An expired SSL certificate can lead to several issues, including:

  • Security Warnings: Clients and monitoring tools may flag the server as insecure.
  • Failed or Downgraded Encryption: STARTTLS connections may fail or fall back to plaintext.
  • Email Delivery Issues: Remote MTAs (Mail Transfer Agents) may reject or distrust the server’s identity, affecting mail delivery.