Resolving Local FQDN Certificate Warning during Second Exchange 2019 Installation
If you're reading this article, you've probably installed Exchange 2019 and noticed that the network is running slowly as you migrate mailboxes. This guide will help you resolve the local FQDN certificate warning that often appears during a second Exchange 2019 installation.
Understanding the Issue
When installing Exchange 2019 for the second time in a network, you might encounter a certificate warning related to the local FQDN. This warning appears because Exchange 2019 uses a self-signed certificate for the local FQDN during the initial installation. When you install Exchange 2019 a second time, the new server doesn't trust the self-signed certificate from the first server, causing the warning.
Resolving the Certificate Warning
To resolve the certificate warning, you can either trust the self-signed certificate from the first server or replace it with a certificate from a trusted certificate authority (CA). We'll cover both methods in this section.
Method 1: Trust the Self-Signed Certificate
To trust the self-signed certificate from the first server, follow these steps:
- Export the self-signed certificate from the first Exchange 2019 server:
Get-ExchangeCertificate -Server <ServerName> | where-object {$_.Services -eq "IIS"} | Export-ExchangeCertificate -Path <PathToSaveCertificate>- Copy the exported certificate to the second Exchange 2019 server.
- Import the certificate on the second Exchange 2019 server:
Import-ExchangeCertificate -Path <PathToImportedCertificate>- Trust the certificate on the second Exchange 2019 server:
Enable-ExchangeCertificate -Thumbprint <CertificateThumbprint> -Services IISMethod 2: Replace the Self-Signed Certificate
If you prefer to replace the self-signed certificate with a certificate from a trusted CA, follow these steps:
- Request a certificate from a trusted CA.
- Install the certificate on both Exchange 2019 servers.
- Assign the certificate to the services on both servers:
Enable-ExchangeCertificate -Thumbprint <CertificateThumbprint> -Services SMTP, IMAP, POP, IISAdditional Considerations
Here are some additional considerations to keep in mind when resolving the local FQDN certificate warning:
- Ensure that both servers have the correct time synchronization.
- Verify that the firewall is properly configured to allow traffic between the servers.
- Monitor the performance of both servers during the migration to identify any bottlenecks or issues.
References
- Microsoft Docs. (2021). Exchange Server Certificate Management. https://docs.microsoft.com/en-us/exchange/certificates
- TechGenix. (2021). How to fix the Exchange 2016 certificate warning. https://www.techgenix.com/exchange-2016-certificate-warning/
- Exchange Server Pro. (2021). Exchange Server 2019 Certificate Management. https://www.exchangeserverpro.com/exchange-2019-certificate-management.html