The mail server cannot send mail

Description - An on-prem hosted email server is receiving outgoing email rejections.

Indicators of this issue - The email server can’t send mail since installing the Bigleaf service.

Potential Causes

  • Bigleaf Support has not yet created a reverse DNS record for the mail server at a site.

  • The email server was not updated to use new Bigleaf-provided IP addresses.

  • Firewall rules or routing policy have not yet been updated to use the new Bigleaf-provided IP addresses.

Tests and Solutions

  • Create a reverse DNS record

    • Contact Bigleaf Support to create a reverse DNS (“pointer”) record, where your email server’s IP address resolves to a “” domain name, which is used by other servers to verify your email server’s identity.

  • Verify the network path and connectivity for the email server to communicate with the internet and other mail servers.

    • Check that firewall rules or routing policy allow 2-way communication between the email server and remote hosts.

    • Use the tcpdump function on the Troubleshooting tab of the Bigleaf Web Dashboard to identify if email traffic is communicating 2-way across the Bigleaf service. Filter on the host address of the on-prem email server or TCP port used by your email server.

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